What's wrong with my tank?

[CReeves]

I have a 30-gallon tank with two oscellaris clownfish, a wrasse, a firefish, three snails and two corals (an Australian Duncan and a torch) and a bubble-tip anemone. I woke up to find the corals/anemone all closed up and the fish sluggish/discoloured and on the bottom of the tank. The wrasse and firefish just died. Most of the algae disappeared overnight and I've done tests for ammonia (a little up, but I added Fritz Zyme 9 to stabilize it) and Ph/nitrates/phosphates were normal. Help – I don't want to lose my clownfish!

 

[FishFinatic77]

Bump

 

[Colin_T]

What is Fritz Zyme 9?

If the fish or corals ever look sick, or if you lose a fish, do a 75-90% water change and gravel clean the substrate immediately, and reduce feeding to once every couple of days for a week or two.

Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Make sure the salinity (salt level) of the new water is the same as the tank.

If you are using artificial marine salts, make some up and keep it in a bucket with an airstone to mix the salt and water. Marine salts need at least 24 hours to mix up properly before using it in a tank with livestock.