I just downsized from a 55 gallon to a 29 gallon. The new tank is a little overstocked at the moment because of the change, but a friend will be taking some of the fish in just a few days.
My giant danio has been getting quite fat, and I thought it was just because it is an adolescent and is still growing. Now that it is in the new tank, I can see that the stomach is severely bloated and the scales are sticking out from the body like a pinecone. I will attach a photo. The upside-down image is his reflection at the top of the water. He is also beginning to swim slower and slower, but aside from this and his appearance all seems well. He eats like a pig! Is this dropsy?
Tank parameters: ammonia 0ppm, nitrite 0ppm, nitrate 10-15ppm. Inhabitants are 1 giant danio, 4 zebra danios, 3 neon tetras, 4 black widow tetras, 3 cories, 1 swordtail, 1 juvenile Angel, 2 red-eyed tetras, and 1 female betta. All get along swimmingly, so the problem should not be due to fighting.
Could stress be a factor?
Is there anything to be done for the fish? I have heard that dropsy is nearly incurable. Does the fish need to be in a hospital tank? Until this point I have found moving the sick fishes to be so rough on them that it actually finishes them off rather than aids in healing. Could adding a bit of salt help at all? What about raising the tank temp (it is currently about 78 degrees)?
Thanks for your help - this is a favorite fish as my husband bought him for me for Mother's Day. :)