I bought 6 medaka rice fish online about a month ago, 3 were DOA, the other 3 were fine. I think I have two males, one female. They have been breeding for about 1-2 weeks and the female spawning every day.
They are in a 40 gallon with red blue eyed neon rainbow fish, cory cat fish, khuli's shrimp and snails. The tank is heavily planted, with planted and floating plants, lots of caves and hiding places for the bottow dwellers. All very peaceful fish, with the rice fish being the bigger than the red blue eye neons.
40 gallon breeder
nitrite - 0
nitrate - 40
Canister and sponge filter, providing more than is required
I just noticed, what I first thought was the typical clutch of eggs, but upon closer inspection it looks more like a tumour or something on one fish's stomach. It wasn't there yesterday.
any ideas what it is, what could have caused it and more importantly what I need to do.
Thank you so much in advance.