I use Volck Oil spray which uses emulsified non-toxic mineral oil. I'm not sure how well it will play with fish, but I don't think it will affect them. It works by smothering the bugs so it only works on the bugs you spray it on. There is no preventative effect.

Ty for the product name.

I have only had them on plants in the house, and I have a tedious way of dealing with them. I don't know how well it would work outdoors or in large areas though. I use alcohol on a Q-tip to clean as many as I can off the plant, and repeat every few days until I don't find any.

That is the only non-toxic way I have dealt with them. The only other remedy I have is tobacco tea sprayed on the plants....really nasty stuff.

Besides, they're too small for me to see clearly.

Tobacco Tea sounds like it would work well. And I wouldn't mind using nicotine for it's intended purpose. If the Volck won't work with fish I'll look into that.

but I use it very sparingly and locally because it is toxic. I have only used it twice, once to get rid of white fly on a bush, and the other on spider mites on some flowers. But I used it only on those plants. It probably would kill the fish. And if you get it on your skin, the skin dries and peels....ick.