Overdose Of Tetra Algae Control

[margaretd]

Apparently I overdosed my 20 gal aquarium with Tetra Algae Control yesterday because 2 of my goldfish are dead, and the others are acting very sluggish. I immediately did a 1/3 tank exchange, plus put the carbon back in, what else can I do?

[Lady Hobbs]

When adding any chemicals, it's best to add oxygen to a tank via airstone or bubbler. But in the case of algae, best to do your own cleaning of it rather than resort to any chemicals. You probably have killed off your bacteria now and will have to watch very closely due to ammonia spikes.

You can get algae for several reasons and better to figure out the cause. Green water is often from being too near a window and the tank getting sunslight. Other algaes from lights being on too long.

I don't know how many goldfish you have, but I would not replace those that died. Even one in a 20 gallon is plenty and "pushing it" and that would only be a fancy.

You may want to do another water change. Could be that chemical is burning their gills.