Ich or fin rot

[Petfish]

My fish are dying 6 and counting. They have the white spots which would lead me to think ich. However after having the white spots for a day I started noticing that the fins were detertating. I have been my tank rid ich plus for 5 days now. I have lost 3 guppies and 3 catfish and thoughts would help

[wrm130]

how long has the tank been running?

how large is the tank?

[Petfish]

It's a 20 gallon tank it has been running for 5 months. Before all this started i added my three guppies and three pepper catfish that i had for around 2 months in a seperate ten gallon tank and there was no indication of illness in any of the tanks and then this hit.

[blueknight0303]

major environment changes will stress out fancy guppies and produce ich and will pass on this parasites to other fish in the tank. fancy guppies are really sensitive. your 10 gallon tank probably have different parameters than your 20 and this could trigger ich.