Originally Posted by Aiken Drum
You should definitely be concerned with the injuries to your fish. Its likely to be caused by the fish getting stuck and struggling to get free. I would remove any decorations that are likely to trap a fish, especially now it has happened twice. Its also possible the other fish got at the trapped fish and made things worse. Have you witnessed any bullying?
Adding 3 goldfish at once into a 40 gallon tank is a lot of new bioload and it could take a while for your cycle to catch up. Do you know your water parameters? Poor water quality could be making things worse.
Can you quarantine the fish in question? Lots of clean water and a stress free environment will give your fish the best chance of recovery.
Longer term a 40 gallon tank isnt going to be big enough to keep all those fish in there when the goldfish get to adult size, especially the comets. Do you know what the bottom feeders are also?
The bottom feeders are two bristlenose pleco. The water has been foggy since I put the goldies in, I’ve been cleaning every other day (5-10 gallons). I’m going to set up a quick quarantine tank for the fancy before I go to work.
I removed all the decor that she could get stuck on, but left the smaller ones for the pleco’s to have as dark hiding spots. I have not seen any aggression towards each other. Everyone is pretty active and eating well.
I do not know the exact water parameters. The water is conditioned city water and none of my other fish have had issues with the water.