My fantail floats at the top of its tank after eating, paddling to stay in its position and not be spun round by the tank current. It looks bloated with one side being larger than the other. The fantail spends time at the bottom of the 75 litre (20 gallon) tank but only through sheer determination and very strong strokes - unlike its tank mate that swims up and down effortlessly. Once it stops its strokes it goes back up to the top.
I feed the two fish once a day in the morning. The diet is varied (flakes, brine shrimp and peas). The water parametres are fine and I make a partial water change every four days. The tank has been running for six months. The temperature is 26oC.
Once the fantail goes to the loo early in the evening, it is back to its normal power-swimming behaviour, going up and down effortlessly. This behaviour has been going on for about three weeks.
Please help?
Thank you.
