Max Posted February 17, 2021 Share Posted February 17, 2021 Hello everyone, after watching Corys livestreams regularly, and after researching myself online but not finding a solution, I hope someone from here can help me. I have a 350L (92 gallons) community tank with the following fish: 5 young angelfish 2 honey gourami about 25 rummynose tetra about 30 amano shrimp 12 Otocinclus 9 Panda Corys 3 different kinds of nerite snails 20 (now maybe 12) Corydoras habrosu You can see photos attached, it is a planted tank that is now running for around 4 month. Water parameters: ph 7.5 / gH 12-13 / kH 11 / NO2 0, NO3 maybe around 10 mg/l before a water change / temperature 26-27°C (around 79 F) I do a water change of 30% every 1-2 weeks, I usually follow Corys advice to rather test the water regularly instead of overdoing it with the water changes, I also have a decent amount of plants, I think/hope especially my floating plants help with the NO3. I have to say that all animals except the Corydoras habrosus seem to do very well: My two larger angelfish already layed eggs once, my Panda corys show breeding behavior, my rummynose tetras are bright red, basically all my female amano shrimp carry eggs, my honey gouramis also build bubble nests, the otos have a nice, round belly. Only the Corydoras habrosus keep dying. You might think the angelfish attack them because of their size difference, but this is not the case. When feeding pellets etc, the angelfish eat on them side by side with the corydoras and never get aggressive in any way. They also don't care about the amano shrimp, which are relatively large already. I started with 12 habrosus, as they are my favorite kind of Cory. In this phase, maybe 3 or 4 died. I suspected my very aggressive apistogramma agassizi female, so I moved the apistos to another tank. After that, the dying stopped for a few weeks, so I bought new ones to get up to about 20, which was my original goal to have. Now, probably 8 or so have died in the follwing pattern: On day one, one habrosus swims around the top of the aquarium a lot, and seems to not want to or be able to get to the bottom of the aquarium. On the next day, it is dead. I think I have lost one fish every day for the last few days, today it was 2 at once. Yesterday, I saw one unable to control its body while swimming. I think this speaks to a swim bladder issue. What I don't know is why it is only affecting the habrosus, any why only one or two at a time (all the others seem fine at that point, until one of them starts with the same behavior). They eat normally with the other fish. I have to say that I don't have sand but round gravel in the aqaurium, but I don't see them trying to dig into it to get food. They mostly chill on plant leaves when not eating etc. I got all of them from the same source, it assume they might be wild caught so maybe they are use fragile? Another theory I had, I have an O2 diffusor in the output of my filter that adds air bubbles similar to an air stone. I read that maybe these small bubbles destroy the swim bladder of those small fish? Or maybe my tank is too high / the pressure is too high for those small fish? (around 25 inches high). I would really like to save the remaining habrosus, but I also don't want to do large changes in the aquarium that could distrub the other fish that all seem to do fine. I reduced the O2 diffusor to produce less bubbles a few days ago, but since then 3 still died (maybe the damage was already done if that was the reason). Really I would just like to know if anyone has any alternative idea what I could do or how to find out the actual reason for their problems. Please tell me if I should post any further information. Best, Max Link to comment Share on other sites More sharing options...
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