Brown Marks And Fish Mortality Issues

[steve2010]

I'm a couple of months into having my new aquarium, having lost about 12 fish so far (it wasnt properly cycled but we wont go into that here).

I now have one guppie and five harlequins (none of the harlequins have died, all the casualties have been guppies, which died one at a time, about one every 2 days which i found odd)

Anyway, it appears to have become stable. No deaths for a few weeks. I have a green plant which has quadrupled in size since being in the tank (it is now at the top and I suspect its rootball is quite extensive!), and a red plant which has grown but about double its size.

But now I'm getting a lot of brown algae build up on the glass, filter top, gravel and plants. Basically everywhere, especially where the light is on it. After a few days the brown turns green. The water appears clear.

What can I do to stop this fast build up? Is there some chemical I can add to stop this? I intend to do a water change tomorrow and trim down the green plant to about half its size, and vacuum the gravel, clean the glass etc.

But should I have to do this? How often should I be changing water (and how much) and cleaning? The tank is understocked, but I have been holding off until it stabilised. Perhaps now is the time to add mroe fish, but I will stick to harlequins for now as they seem to survive better!

 

[karin]

Sounds like diatoms or brown algae. See

http/www.theplantedtank.co.uk/algae.htm

The above site states about Diatoms:

Description Forms in brown patches on the glass, substrate and plants.
Cause Usually found in newly setup tanks due to silicates and ammonia as the filter and substrate have yet to mature.
Removal Can be vacuumed out or wiped of the glass with a soft cloth. Usually disappears after a few weeks when the tank has matured. Otocinclus will eat it.

Given the fish deaths I wonder if you had a bit of ammonia spike or imbalance here or there. Could have killed the fish and promoted this algae.

Also, guppies are somewhat fragile fish. Probably because they are so prolifically bred. A few deaths are expected and will depend on the quality of your supplier.

 

[steve2010]

Thanks. I have cleaned the tank today and done a half water change, and all appears well. I also tested the ammonia afterwards, which is reading 0.25 right now. But I am unsure of the best way forward to ensure the ammonia falls to zero.

What is the opinion of Pets at Home as a fish supplier?

Also, I have a small snail in the tank (think he came in on a plant), he seems to hide in the gravel a lot and gets sucked up by the gravel vacuum. Is he doing any harm? He has grown to about double his size since being in there.

Thanks.