Someone help

[Brookelynnb]

I don't understand how you never change yours. After a month and a half, it's so disgusting and covered in poop, you have to change it. The people at the pet store said I should be changing the filter (carbon one) every month.

I'm getting different things said to me, so it's a little confusing.

 

[Mebbid]

I just swirl it around in tank water. Honestly, its primary function is to hold bacteria. A certain degree of grossness is expected

Keep in mind that when people at a fish store are telling you things they are trying to sell stuff to you.

Filters don't need to be changed until they are completely decomposing. I know the filter companies recommend that you change them monthly, but they are trying to make money off of you.

Carbon is nearly useless for regular use in an aquarium. Its primary function is in removing medicine from the water. Other things that it does is remove smells and can make the water clearer in very few circumstances.

 

[Mcor]

Yeah a good swish about in a bucket of used tankwater is all your sponge needs. All the mulm and slime and filth is what your bacteria is living and reproducing in. Clean it enough that it isn't clogged up, then stick it straight back in. Keep going until it is literally in tatters, then replace it, but put some of the old sponge in with the new to seed the bacteria.

 

[librarygirl]

Ok, changing the filter regularly is part of the problem. Filter media shouldn't be replaced unless it's literally falling apart and even then only replace a small portion at a time. Changing the filter constantly isn't allowing the bacteria to properly grow which is probably why the tank has constant ammonia readings. Swishing the media in old tank water during a water change every month or so help keep it clean without losing the bacteria.

Is the one goldfish all you have in the tank or do you have other fish? What kind of goldfish is it? A 20 gal for one goldie is minimum; as it grows it'll need a larger tank. If it's a common, comet or one of the larger types it will eventually need a pond.

Goldfish are messy as you've seen so they need extra filtration. A tetra 20 on a 20 gal tank isn't sufficient filtration I'm afraid.

Also test strips aren't very accurate; investing in a liquid test kit would be best.

Here are two articles for you:
Guide to Starting a Freshwater Aquarium - Aquarium Advice
http://www.myaquariumclub.com/goldfish-101-11174823.html