I have a fresh water aquarium (150Lt) that has been set up for over a year with:
4 Bristlnose catfish.
6 Male Guppies.
the largest fish wld be two inches, they're all relatively small at the moment. Have done a water test and all parameters are normal. have used two different kits. I have driftwood, natural gravel and live plants in my aquarium. I don't use chemicals in my tank, never have. I have a large external biofilter for the tank. Give the tank about 12 hours of light a day. It's heated at 23'C.
I've recently lost alot of fish. the tank may have been a little over crowded but i was doing regular water changes and the fish were all quite small. I often get rid of fish if there becomes too many, recently got rid of all female guppies. My problem is that fish have been dropping off one by one. I thought maybe a disease or the water but they literally drop off one by one. I've bought other fish to replace which was probably a silly thing but i just thought the fish deaths were random but then they've continued over the past month or two. I've lost 2 upside down catfish, 1 bristlenose, 3 yoyo loaches, few guppies, and 1 corydora.
I had wondered if it may have been due to the driftwood in the tank as some of it has developed a weird grey/black moss/algae on it. the catifish don't touch it which made me wonder what it is. In saying this i just pulled the driftwood out to soak it in diluted bleach for a day to try and kill the moss and so regrettably found some fresh bristlenose eggs in the wood! Completely devastated about this as i was hoping they would one day breed and this was their first batch. My male albino seemed a bit distressed when i took the wood out and i soon foudn out why. And i had to wonder that if the tank was in an unhealthy state would they want to breed?
Anyways that's my dilemma. as i said everything seems fine and the only thing out of place is this weird moss that has developed.
hope someone can help.