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Thanks. The fry are about 10mm long now. So maybe they will grow to about 15-18mm in the next couple of months and have a chance of surviving the UK winter.

Hi, another 2 weeks of vacation ..... a report from home says my medaka are "still alive". The 4 months of summer at my sub-tropical location have an average daily day/night temperature of 30degC ..... which is why my medaka grow faster than yours. Supposedly slower growth results in better coloration so your medaka may look better than mine.

At 18-20degC I find medaka are reasonably active and eat as normal ... except in smaller quantities than at 28-30degC. For Jan/Feb in winter at my location, temperatures may be average max 20 and average min 12 with lows of 6 for several days at a time. All my medaka survive OK outdoors in unheated tubs except I may put very small juveniles and some of my more delicate medaka in a heated tub at 18-20degC I suggest there's a general 15/10/5 guideline for water temps for medaka (maybe does not apply to delicate varieties) ..... ... at 15degC they eat moderately; are moderately active; grow very slowly ... at 10degC they eat very little; are slow moving; stop growing ... at 5degC they do not eat; are completely inactive at the bottom of the tub. Therefore even small juveniles probably have a reasonable chance of surviving in temps above 10degC. At temps 10degC and below probably only 18-20mm long juveniles have a reasonable chance of surviving..

Sometimes I think it's good to let medaka hatch naturally in a pond. The survivors possibly have stronger genes than many hatched artificially.

@@km-qh3rs I tend to only put out the spawning mops mid-July. This means I catch some of the eggs and fry that might not be strong enough to get through winter. I raise these inside and put them out the following spring (or sell them for a couple of quid/give them away) My thought process is that the ones that hatch earlier in the pond in spring/summer, should they survive being eaten, will have a few more months of growth. That seems to allow them to survive winter.

They are not banned. Aquarium shops are not supposed to sell them as outdoor fish if they've imported them under a certain licence as an indoor aquarium fish. That's where the confusion comes from. It's perfectly legal to keep them in outdoor ponds and give them to friends if you wish.

I'm always interested in raising medaka entirely outdoors ..... but then that's easy for me in my sub-tropical location. I don't live in the UK and I'm not a lawyer so I may be wrong about this ..... but my understanding is that there is no law that states it is illegal to keep medaka in outdoor tubs and garden ponds. However it appears there's an advisory note from a fish importers trade organization to retailers that, in accordance with their license under the Import of Live Fish Act, they can "only sell medaka for indoor aquariums" and that the retailer should ensure customers understand that medaka "cannot be kept in outdoor ponds or barrels". However obviously when customers get the medaka home, the retailer has no control over where the customers keep the fish and it appears to be incorrect for a retailer to say they "cannot" be kept outdoors.

I've heard that koi are not much good at keeping mosquito larvae under control. If this is correct, then medaka should be reasonably safe from predation by koi. Maybe another way of looking at it ......... do the koi breed in your pond? If so, then medaka fry should have a similar chance of survival as koi fry.

@@km-qh3rs Thank you!

Thanks

Good points Jan, I don’t have any fish yet so need all this valuable information ✌️

@@gayefanner731 well I am not an expert, even tho I've raised quite a few species of fish. Usually the same principles apply. And I always take the better safe then sorry route :) Best luck to you :) Ye, and keep the videos coming, you have good ideas and I like to watch them.

I understand your point of view. On the other hand, I've never observed that adult medaka are fin nippers and never seen them try to eat 1cm long juveniles. Also I drop food at different areas in the tubs and pond so that all fish have a chance of eating.

Thanks. I still have a few more weeks of vacation but will try to post a new video soon.

They were hungry at the time of filming. However, if water quality is good and the medaka are healthy, their activity rate depends on water temperature. At present, water temperature in my tubs is about 28degC so the fish are very active. At, say, 18degC they are less active.

Hi, the netting is there to prevent dragonflies from getting near enough to the water to lay their eggs in the water. If any eggs hatch out, dragonfly larvae are one of the worst predators for killing and eating medaka.

@@km-qh3rs ohh i see, thank you. What do dragonflies larvae look like? I want to be able to identify them so my Medakas are safe.

@@yuzumeow hi, I posted a video here showing dragonfly larvae about 2 months ago.

Thanks.

I don't live in the UK and I'm not a lawyer so I may be wrong about this ..... but my understanding is that it is not illegal to keep medaka in outdoor tubs and garden ponds. I assume that the information you have seen has arisen from this article (or similar) ornamentalfish.org/industry-warned-to-ensure-oryzias-species-must-only-be-sold-for-indoor-aquariums/ . This appears to be only an advisory note from the trade organization to retailers that, in accordance with their license under the Import of Live Fish Act, they can "only sell medaka for indoor aquariums" and that the retailer should ensure customers understand that medaka "cannot be kept in outdoor ponds or barrels". However obviously when customers get the medaka home, the retailer has no control over where the customers keep the fish and it is incorrect for a retailer to say they "cannot" be kept outdoors.

I've had the clay pots for many years ..... previously with drainage holes for plants ..... then plugged the holes to use for miniature water lilies ..... now as medaka tubs. Still got 2 or 3 more clay pots I may convert to medaka tubs, but may be lazy and buy some good quality plastic containers.

Nice to hear from you. I admit I used to generally ignore problems arising from very soft water and it's highly probable that, to some extent, my fish suffered from that. However I'm now trying to amend my ways and to see how much limestone and oyster shells I need to provide a reasonable buffer and maintain the fish in good health.

Sub-tropical Asia. Very soft water ..... pH of tub and pond water about 6.8 until very heavy pH 5.0 rainfall drops the pH to 6.0 or below. GH, KH about zero.

@@km-qh3rs I am in south Louisiana, USA and have that kind of water too!

Thanks. I've got a few bits of recorded video I may tidy up and post if I have the time. Always very busy on vacation.

Thanks.

Thanks. Off to the UK to see grandchildren.

Thanks. Really there's not much to learn. Medaka are tough little fish but they certainly benefit from good water conditions, reasonable water temperatures and, if possible, some sunshine or bright daylight.

@@km-qh3rs Thank you very much. Hope you’re enjoying your change of scenery ✌️

Thanks. This is really my own personal video diary. I just found it's remarkably easy to keep the diary on RUclips. Happy that others find it useful.

Selective to the extent that I form breeding groups of all one type of medaka e.g. all orange medaka. However I've learned previously not to be too fussy about selecting only the very best looking fish to form the group if I only have a few fish of that type to select from. I only feel comfortable when I've reached what you might call "critical mass" of, say, 20 fish of a particular type. For example, if only, say, 7 or 8 orange medaka then I'd breed them all ...... if, say, 20 orange medaka I'd select the best 9 to 15 fish to breed. Personally I'm not that interested in trying to keep the most spectacular looking types of medaka outdoors and I'm happy with a shoal of reasonably good looking, well colored fish. I may be wrong but I think that a certain amount of genetic diversity helps maintain a reasonably robust line of fish for keeping outdoors ........... which is why I aim for a breeding group of that size even if the fish are not all of the very best color etc.

I'm a retired civil engineer. Travelled quite a bit ..... even been to Canada a few times ..... but only BC and Alberta. My family are not fish keeping enthusiasts ... but they're happy I have something to keep me out of trouble .... also they're somewhat amused that I have a RUclips channel in my old age.

Hi. I'm told that these days the large 100 yen stores in Japan have so many varieties and types of stuff for sale that it can be quite overwhelming. Some years since I was in Japan but at that time I was not interested in medaka.

Just found your channel and I've subscribed. I'm thinking of getting some medaka for outside. Where did you source your original fish from?

I always forget to count .......... but I'm sure I've produced more than enough. However I'll have to wait until September to see how many survive the very hot and rainy summer weather.

@@fsr170409 Hi. There are none in any local fish stores but I managed to find a source on Facebook willing to let me have some. Had to drive quite a way to collect them and they are not pure bred strains. However they are reasonably colorful and I'm happy with that.

Sub tropical climate? So you're not in the UK then.

@@StuartChignell Hi. No, not the UK .....I'm in Asia. But a friend sent me this link about UK retailers only selling medaka for indoor aquariums and to ensure customers understand they cannot be kept in outdoor ponds or barrels ornamentalfish.org/industry-warned-to-ensure-oryzias-species-must-only-be-sold-for-indoor-aquariums/ . Presumably it's not illegal to keep medaka outdoors in the UK ... it appears to be just an advisory warning that government may in future ban the import of live medaka if they become an invasive risk due to being kept outdoors.

Hi, I'm in Asia in a sub-tropical climate. To produce eggs like that, your medaka must be happy and healthy in the environment you've provided for them, Looks like in a month's time you may have collected 600 eggs.

@@km-qh3rs aaaahhhh I was hoping you were in the UK like me. Now watching all your videos 😂 I have established tubs outside with 3 different types of Medaka so far. I do have plants including Lily’s and use the same spawning mops as you although use the pool noodle idea. Definitely very addictive and extremely rewarding.

I tend to doubt that liquid fertilizer makes much difference. However fertilizer spikes always seem very expensive to me ...... so I sometimes wrap granular plant fertilizer in some cotton material and bury that in the water lily pot. The idea is that the cotton material will prevent the granules from dissolving too quickly. Not sure if it's a good idea or not but no water lilies have died yet. I regret I don't sell medaka fish or eggs. I couldn't handle the logistics of that and anyway I think people would probably be disappointed with the quality of the fish because my medaka are not pure bred strains.

I put the spawning mop in a 10 liter bucket of water. In about 3 weeks I'll probably tip the water into the pond to give any hatched fry a chance.

Thanks. I'm somewhat elderly and running the channel helps keep my brain active. Always happy to answer questions although sometimes there may be a few days delay.

About 9 to 10 gallons. I've only ever kept medaka in a sub-tropical climate so I'm not really qualified to advise about keeping medaka in a clay pot in your area in -17degC conditions. However I think clay pots are slightly porous and the water in the pores may expand when it turns to ice and the pot may crack. Also my guess would be that there's a high risk of the medaka not surviving outdoors if -17degC temperatures continue for a long period of time. But that's only my guess. Reddit has online an r/medaka community who are usually helpful answering any similar questions you might have.

Hi, depends on how much you want to pay? I think you may find something similar at about US$10 incl. int. shipping on ebay if you search maybe "fish photo observation watching tank box". Not sure if they ship to Canada. I don't know if you're aware that amazon.jp.co has an English version of its website. Search for medaka etc and it will produce lots of results ... e.g. medaka for sale in Japan (do not ship overseas but shows prices in Japan) ...... other medaka related stuff, some of which may be shipped overseas but shipping costs maybe about US$25.

A capacity of 35 to 40 liters ... about 9 to 10 gallons.

I only ever feed powdered fry food ... something similar to Hikari First Bites which I think you can get in the UK ..... feed 3 or more times a day. If the newly hatched fry are healthy and strong enough I've found they have no problems eating that within 1 or 2 days of hatching. I would have thought that feeding liquifry risks severely polluting the water. Fry are very fragile for the first 2 weeks. So, ideally, there would be no water changes for 2 weeks ..... however I may do a 20% water change at the end of the first week ..... but it's essential to do this by using a slow drip method. I wouldn't worry ..... medaka fry at 2 weeks old are still very small and it's not unusual if some have a slower growth than others ..... as long as the fry are swimming about they should be OK. Note that where the parents are juveniles, the females tend to produce smaller eggs than fully adult fish and consequently the fry may be initially smaller.

@@km-qh3rs hi thank you very much for the great advise. Much obliged

@@km-qh3rs Interesting that you do not recommend water changes generally. What about the growth stunting hormones fry are said to release? Thanks for the advice re liquifry

@@H.Ali_08 Maybe I haven't been sufficiently clear ..... as above " Fry are very fragile for the first 2 weeks. So, ideally, there would be no water changes for 2 weeks ..... however I may do a 20% water change at the end of the first week" ..... so I'm only talking about the first 2 weeks and have never suggested that water changes are generally not recommended. In fact, if you listen from minute 8.30 onwards in my above "water changes" video you will note that, for newly hatched fry, after the first 2 weeks I usually make a 20% water change either every day or every 2 days. Also I'll add that I don't believe in growth stunting hormones. As far as I'm aware, no-one has been able to identify chemically exactly what type of hormone it might be. But there may be metabolic change chemicals in water containing large numbers of fish which may restrict growth rate. However, as with all animals, some fish are stronger than others and can reduce any deleterious effects of these chemicals.

@@km-qh3rs Thanks that is very clear. Interesting to know. Despite not getting any eggs at first, I am now inundated since I purchased a heater for the indoor tank. I have a mesh box inside my tank wherein I have placed the eggs to ensure that the eggs stay in 25 c consistently to enable them to hatch sooner. I have also placed plants like hornwort, dwarf water lettuce and water cress within that fine mesh box. This enables the Medaka outside of the mesh box but in the tank to lay eggs on the homemade egg-laying item. I am keeping my two two-week old fry that I had purchased separately in that mesh box to enable them to be at 25 c and increase their metabolism to ensure they grow well and take in maximum food. They appear to be happy. I can fully understand why you are a Medaka hobbyist. It is great fun and satisfying being new to it myself. They are hardy fish that tick every box for me. Only goldfish / koi are hardier as they'll lay eggs in cooler waters. I have an outdoor pond containing goldfish, orfe and koi. When some of my Medaka reach adulthood and 4 cm will I be able to place them into my outdoor pond with the larger fish. I don't think the larger fish will eat the Medaka but could be wrong. You have been so generous with your knowledge but I'll stop asking questions going forward I promise. Thank you for your generosity!

Respectfully, I have a different understanding of the pH of rainwater. My knowledge is limited, but it appears that in pristine areas of the world, theoretically, rainwater has a pH of 5.6 due to precipitation dissolving CO2 to form weak carbonic acid. In areas such as Tibet there is alkaline dust in the air and rain pH may be above 7.0. In tropical rain forest areas there are organic aids in the air and rain pH may be about 4.5. I don't know anything about the UK but this 2022 map nadp.slh.wisc.edu/filelib/maps/NTN/pdfs/2022/pH_2022.pdf shows rain across the USA is within a pH range of 5.0 up to about 6.5. In my area rain pH is about 5.0.

The "hoops" are filter media ceramic rings threaded onto a long zip tie so they are easy to pick up and move around. I take the ceramic rings from my pond's trickle filter so they already contain beneficial bacteria to help deal with ammonia etc when I put them in the fry containers. The rings also introduce micro-organisms into the containers for the fry to feed on. I initially quarantine the rings for a week or so to ensure they don't have bad stuff on them.

Thanks for the suggestion. That's an option, but I've been happy enough with my overall medaka keeping results so I haven't previously introduced that added complication. However I'm now trying something similar and possibly that'll be the subject of my next video

@@km-qh3rs sounds good. im new to medaka raising my first lot indoors. wish I had a garden to have pots like yours.

I have had breeding groups produce a few eggs when the medaka were about 15 mm long ..... so 2 cm fish should be mature enough. I've had a group of 9 fish producing zero eggs ..... but then I found they were all females. I've also found, depending on the medaka strain, some will produce eggs with water temp at 20degC ..... others won't produce eggs until water temp exceeds 25degC ..... most will not produce eggs when water temp exceeds 30degC Some are OK with 11 hours of bright light ..... some need 13 or 14 hours of bright light. Some produce eggs in relatively poor water quality ..... others need good water quality and/or neutral to mildly alkaline PH. Some medaka seem to spawn better when moved to a tub in the sun ..... particularly early morning sun Some females properly attach the eggs to spawning mops ..... others scatter the eggs anywhere. And some groups (and I have one now) don't produce any eggs, even though the fish are fit and healthy and I've tried every remedy I can think of. One option to try ..... in a group some medaka may steal and eat the eggs from females and/or there are so many fish swimming around it disturbs the spawning process. Perhaps try dividing out into breeding trios of 1 male and 2 females and keep in separate bare containers i.e. no substrate and only very minimal floating plants. Say, 20 liter buckets ..... high protein food ..... with a bit of early morning sun...... maybe 15% water changes every few days.

@@km-qh3rs ah thank you very much for the very detailed response. I really appreciate you taking the time to give me those tips. I will try them and it is interesting to hear that you've had Medaka of 15mm length produce eggs. Perhaps they are breeding but my tub is heavily planted which may be a reason why I am not seeing anything. I will try your suggested steps and see if it brings me any success. Thank you very much once again! :)

@@H.Ali_08 One thing I forgot about and left off the list is ...... perhaps don't expect to get very many eggs if the medaka are in a heavily planted tub. Probably many would disagree with my opinion, but I've got no idea why it is often recommended that medaka need heavily planted tanks or tubs. Medakas' natural habitat is mainly open water streams and rice fields. They are surface feeders with upward pointing mouths and their eyes are towards the top of their head so they can more easily see overhead predators ..... and they need at least 12 hours of bright light to spawn (ideally with at least part of that period being sunshine). They will still survive in a heavily planted environment but will be under stress and many appear shy because ..... they can't feed properly from the surface ..... they can't see sideways properly to look for predators perhaps hiding in the the plants ..... they don't get enough bright light within the murky depths. Medaka are at their happiest and healthiest and most likely to spawn in a sparsely planted tub with a relatively large open water surface area and with bright, good quality, full spectrum light. Sorry, long-winded as usual ....... but, as with my videos, I don't have the patience to edit

@@km-qh3rs this is fantastic information thank you. In fact as per your previous advice I removed a number of plants from my tank yesterday. It's great that you are doing these highly educational videos. I think more and more people in the UK are becoming aware of how great Medaka are!

@@km-qh3rs I have purchased an aquatic thermometer and note the water temperature is around 16 degrees Celsius. I note in your earlier comment that Medaka will not produce eggs generally under 25 degrees C however in exceptional circumstances some may produce eggs at 20 degrees onwards. I just have to hope June in the UK brings warmer weathers which will raise the water temperature to around 25 degrees. Atleast this reassures me why my Medaka have not produced a single egg despite being between 1.5cm - 2.5 cm in length. Thanks for your help. I purchased Medaka fish as they are brilliant, versatile fish that tick every box as I'm sure you will agree being a huge hobbiest of the fish.

Thanks. Problems of similar severity to the PH crash are occasionally to be expected when adverse weather conditions occur and you're trying to keep medaka or other fish outdoors. I've had tree branches blown down in strong winds; toxic leaves falling in the tubs; blocked outlets in the tubs causing fish to be washed out of the tub during heavy rain. I've had a bird dying in the pond and polluting the water; etc; etc. I've seen where people have had their tubs destroyed by racoons and similar animals. As a general issue, water temperatures in my tubs may reach about 35degC next month at least half the time. The resulting low dissolved oxygen content at those sorts of temperatures will start to put stress on the fish. At temperatures higher than that, the dissolved oxygen content decreases further e.g at 40degC, there may be considerable stress on the fish. If I have, say, 15 medaka in a tub then I'd expect to lose at least 3 or 4 or even 5 of the weaker fish by the end of the summer due to high temperatures and/or high rainfall and/or high winds. I've probably got more than enough eggs already. No more goldfish ..... the bioload produced by those 5 goldfish was probably equivalent to the bioload produced by 100 medaka ..... at present, I'd rather have another 100 medaka in the pond rather than add new goldfish.

Hi, it's interesting that, once fry reach about 3 or 4 weeks old, I don't see any newly hatched mosquito larvae in their container. Obviously the fry can't eat older mosquito larvae but perhaps the fry are then big enough to either eat the mosquito eggs or newly hatched larvae. Medaka are quite voracious predators and I'm now beginning to wonder if adult medaka are able to eat dragonfly eggs or newly hatched dragonfly larvae i.e. if you start out with a tub with zero dragonfly larvae and you have adult medaka maybe there's no need to worry about dragonflies laying eggs in the tub. I haven't seen any references to this and I don't necessarily believe what I've just suggested ..... so I still cover tubs and pond with netting to keep dragonflies away.

@@km-qh3rs You make a very good point. Timing is so important. This is my first tubbing season so still lots to learn.

Hi, thanks for the comment. Sorry, I've not heard anything about that. However I think there are very long lists of similar prohibitions of plant and animal based items in many countries. However these lists are often so obscure and hardly promulgated that most people are unaware of what may or may not be prohibited.

@@km-qh3rs thanks for the detailed response. I think you are spot on. Thanks and keep up the great work! Look forward to seeing more of your videos re Medaka

Are you aware he lives in Asia? ✌️

Yeah, I also watch a lot of youtube videos at x1.5 speed. My wife often tells me she wishes she could listen at x1.5 speed when I'm talking to her.

If you are getting lots of eggs from your medaka then no need to worry too much. Most of them will hatch without too much care. But with only 15 eggs I assume you want to try to get maximum success rate. Depends on what sort of system you will use but some suggested points to think about. 1. White mold on eggs kills the embryo. So keep a space between all the eggs. 2. Optimum temperature for hatching eggs is about 28degC. Hatch in about 1 week so less time for mold to develop. 3. Hatching at 20degC takes about 2 weeks so more chance for mold to develop over that longer period. 4. Eggs in a small container at 20degC maybe water change 20% to 100% every 1 or 2 days. Eggs in a large container at 28degC maybe 50% every 3 days or maybe no change. 5. Fry are very very delicate for first 2 weeks. Risk of being damaged by change in water conditions or temperature. So only minimal water changes during that period. 6. If fry hatch in small container then only transfer to larger container that has very similar water conditions as hatching container. Transfer by scoop and NOT by net. 7. For first 4 weeks I change water by drip acclimating method. I change 20% each time. 1st change at end of 1st week. 2nd change at end of 2nd week. After that, change every 2 to 3 days during weeks 3 and 4. And maybe continue at that rate for another 4 weeks if I'm really keen on getting good, strong, healthy juveniles for that type of medaka. 8. Some fry feed only 2 days after hatching. I've found some feed immediately. So I feed immediately after hatching. 9. I've heard of the brush feeding method. I feed using a small, long-handled spoon as shown in my video Fry Management - Food. I think it's easier to gauge quantity that way. 10. The above are only suggested points to think about for eggs that are important to you. You could probably ignore most of them and still get a good success rate. Good luck.