Yeah I do water changes every week and I use dechlorinator, the tank use to house an arowana and cichlids. I'm new to guppies and wanted to test my hands on breeding them. I use the one from walmart the tetra safe brand.
Yes it's been cycled years ago I use to raise an ariana, and cichlids, but decided to go into breeding
I have a foot long air stone and a 75 gallon air filter. I haven't tested the water in a long time so I can do that once I get home from work tonight and I'll get back to you with the numbers. Thank you for the guidance!When was the last time you tested the water? Just because the tank is cycled doesn't mean it can't have spikes in ammonia or nitrites. Or very very high nitrates.
I would guess water quality and you should test your water right away. At the very least do a big water change right away. Hanging at the surface is no good.
Do you have the water aerated? Maybe it is lack of oxygen?