pet fish

Question
Hi,
I purchased two black moor goldfish 3 days ago. I have them in a small but roomy tank- they have plain filtered water in the tank with pebbles at the bottom. I also have a oxygen plant in there too. The tank has all of a sudden started to smell! The water is also quite murky but looks clear.. can you please help me?
Thanks, Emilee :)

Answer
Hi Emilee,
Sounds like the usual beginning signs that a tank has started to establish a 'biofilter' or as most people call it 'Cycle' where good bacteria grow and develop colonies in your gravel bed, filter and most surfaces within the tank. They are responsible for taking care of the dangerous ammonia fish produce. When a new tank is setup, these bacteria are not yet present...So we must be very careful when adding fish. If ammonia is allowed to buildup the fish could easily die or suffer ammonia burns.

Most aquariums take about 4-6 weeks to cycle. Until then lots of partial water changes and ideally water testing (most petstores will do it for free) should be done to keep the fish safe through the cycling process. Ammonia will naturally rise and then fall as another dangerous chemical "Nitrite" a by-product of ammonia from the bacteria appears. Eventually both levels will descend and the final end harmless product 'Nitrate' appears and it is kept in check by regular partial water changes.

Goldfish like Black moors produce a much bigger bioload (waste load) in the aquarium -- more so than other fish. They are also very sensitive to pollution.

A healthy aquarium should -only- have a pleasant somewhat rich earthy/healthy soil smell. If it ever is unpleasant that is a sure sign that something is wrong.. Likely the ammonia has built up in the tank.. Different species of bacteria are developing because of the sudden nutrient overload and their numbers are clouding the tank (This is known as a bacterial bloom)

While these bacteria are not dangerous in the sense that they could cause infections. Their presence is a red flag the aquarium is not balanced.

My best recommendation is to do a large 50-75% water change to remove as much of the builtup ammonia as possible. Be sure to either use a gravel vacuum or if you don't have one (I highly recommend getting one) then use a cup to scoop out water.

Thereafter, I feel daily 30% water changes are best to insure your black moors are not subject to drastic high ammonia levels. Unless you can get a test kit, theres really no precise way to know just how toxic the water may be.
Water changes will not keep your tank from cycling (many sources will say that they will)

These water changes should continue for at least 4-6 weeks. And remember to use dechlorinator water conditioner (like stress coat) to condition new water.

I hope this helps and good luck!!
Susan~