Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
There are very few bacteria in the water. They grow attached to surfaces with high oxygen such as most types of filter media (not just specifically bio media). Water changes will not reduce the population of bacteria, just reduce the levels of toxins.
Who said anything about over feeding? It is a simple formula:
The more nitrogen you add to the tank the more nitrogen you have to remove.
Nitrogen enters the tank as protein.
Nitrogen leaves the tank as...
ammonia, nitrite, nitrate, via water changes.
plant trimmings (plants incorporate nitrogen in their leaves as they grow)
very few other ways.
Since your tank is not mature biologically, the nitrogen in the protein is getting turned into ammonia and nitrite, but not much is getting turned into nitrate, yet.
To alter the basic formula you need to work it from both ends:
Reduce the N entering the tank (feed less, especially high protein foods).
Increase removals (more frequent and larger water changes).
Increase removals by getting plants thriving in the tank. Since this takes time, you are back to the first 2 options.
Ammonia and nitrite are toxic to the fish. You need to remove them NOW, not keep on waiting it out. Water changes can help, but the fastest way to solve the properly fix the problem is to get the bacteria going right away.
To reduce the ammonia and nitrite you need more of the right species of bacteria. This is available from several companies, but you need to be careful which species of bacteria you buy. The right species is Nitrospira. The other bacteria found in the bottle with Nitrospira will also be the right ones.
If the bottle does not specify Nitrospira then it probably has the older species of bacteria, that are now known to not be so active in aquariums. Do not bother with any of these.
Here is how I have handled this in the past (friend's tank with too many fish, no plants, and a problem filter- the bacteria had died):
1) 2 x 50% water changes, back to back, including thorough gravel vac. Use a dechlor that locks up ammonia (read the label- not all do).
2) Add Tetra Safe Start (it is one of several products with Nitrospira, and the one I could find on short notice)
3) Monitor the tank.
The next day there was a trace of ammonia, gone by the day after. No nitrite ever showed up.