Did i poison my fish???

Question
Hi! I have several years experience w/tropical freshwater fish, which is why im almost embarassed to be posting this question. In my 10 gallon fry tank, I had an algae bloom, my 1st experience w/this problem ever. I took the advice of someone else (covering the tank, etc for 24-36 hours), that didnt really seem to help at all. WELL, i then tried the chemical route, Algae Destroyer advanced. It says to add 5ml for each 50 gallons, repeat dose every 3 days. I added about 2 ml.....not much difference. I got a little impatient and added some more on the 2nd, instead of the 3rd day. The algae began to disappear...and so did the lives of my fry. Within 24 hrs, approx 15 of 60 were dead. Totally confused, I did a 40% water change and put some meds and stress zyme in the tank. WELL, the next morning about 45 of the 60 fry were dead, as well as the snails. DID I POISON MY POOR FISH??? Its the ONLY thing that i can figure killed them. Ive never had mass death like this before!! Of the 15 or so that survived, 4 or 5 are....'mental', it seems, swimming and acting very erratic. I declared a state of emergency and removed the 15 survivors, put them in a breeding tank, INSIDE OF MY ADULT TANK. They seem slightly better. Currently, i am emptying the contaminated tank, and plan on cleaning the hell out of it. Any thoughts would be appreciated....besides the obvious--dont poison my fish next time.

Answer
Good morning, Patrick, thank you for your question...

I am terribly sorry about this catastrophe. Adding the fry to the main tank was what I would have done too, given the circumstances. Unfortunately, chemical algaecides are definitely NOT recommended - especially for fry tanks. Fry are especially sensitive to water quality. You likely destroyed your biological filtration, not just the algae, with this additive...it happens! Probably the person who recommended it to you did not dose full strength and didn't dose in a rearing tank. Mileage varies with chemicals.

After you clean your fry tank, set it up normally and add some used filter media from your main tank as well as established gravel from the main tank to speed up the cycling process. Toss that Algae Destroyer in the garbage! Here's one review from a website I trust...

http://badmanstropicalfish.com/profiles/profile4.html

...About a commonly marketed algaecide. My experience using Algone has been a successful one, you can purchase their product directly from their website, www.algone.com - however, the best thing for you to do is to determine why you were having the algae outbreak to begin with.

Are you by any chance using incandescent lights (two screw in bulbs) as the light source for your 10 gallon? If so, you found your problem. My quarantine/hospital tank was outfitted with these and I have relocated the hood to the utility room, where I will use it only in an emergency breakdown. Switch to a fluorescent strip with aquarium bulbs (not daylight or cool white) and your algae problems will likely disappear, if you were using incandescents before.

If this is not the case, then excess nutrients/organics are your problem. Fry tanks ARE messy. Fry foods are generally high in protein, the biggest polluter as far as food goes. The snails are a good idea as scavengers but you can also try a bristlenose or a couple of otoclinus, aka "otto cats" if you can acclimate them - make sure you choose healthy specimens from the LFS, otos are a bit delicate. This websites lists other choices, a few suited to a 10 gallon:

http://www.thetropicaltank.co.uk/algae.htm

The website http://freshaquarium.about.com will have tips on  keeping algae in check. This is a "classic" example of an algae problem one user had. You may want to have a read:

http://freshaquarium.about.com/od/algae/a/reality001a.htm

Oh! Do keep in mind that invertebrates such as snails are extremely sensitive to chemicals, including medication. You'll want to relocate them when you dose the tank - but all in all, stay away from "quick fix" chemical solutions! Increasing filtration, aeration, running high efficiency carbon in your filters - these are all better alternatives.

Good luck with the survivors, Patrick - I feel for your loss! Keeping aquariums is all about experiences, I know you have learned and grown from this one.

Happy new year,
Nicole