Why are there tiny bubbles forming on my aquarium power filter sponge?

Question

I bought a flowel power filter for my approx 25 gallon aquarium containing 1 Oscar, 2 Blue Gouramis, 2 Iridescent Sharks and 10 White Convicts. These guys produce a lot of waste and I change about 2 gallons of water and run the filter for about 2 hours everyday.

Now, the sponge in the filter has become dark brown and I see tiny bubbles forming on the sponge. Why and how is this happening?

Answer 1

The brown is algae and the bubbles is the oxygen it's giving off as a result of photosynthesis. This is from the amount of nutrients in the tank. I'm not sure why you're only running the filter 2 hours a day, unless you have a backup filter - these should be on all the time, or the bacteria in the tank and on the filter media won't have enough oxygen to reproduce to the numbers you need for converting the ammonia and nitrite (which are toxic to your fish) to nitrate.

I hope you realize that your tank will be too small to keep the fish you've got for very long. The oscar will need a 55 gal (mimimun) just for itself, and the iridescents will get at least 12" and may grow to 3-4 feet long each. The waste you see now is nothing compared to what you'll see in the future.

NOTE: You could try changing a little more of the water volume - maybe 20 -25% 2-3 times a week to remove more nutrients.

Answer 2

The sponge in the filter is cleaning up the debris that floats in the water.

Your aquarium is much too small for the amount of fish you have. Your oscar will need that tank to himself before you know it. He will eventually eat all the fish. Gouramis and sharks do not belong with those cichlids. The convicts will get more violent as they get older. And iridescent sharks are friendly easy going fish. So are the gouramis. It's cruel!

You need a proper filter that runs 24 hours a day. Not two hours a day. If you mean you have a polishing filter, you should only use it once a week. And you should only change the water once at week and only 10 percent of it. Once every 6 to 8 weeks a 50 percent water change will do fine, and once a year a 100 percent change will be necessary. Clean the filter and it's media, and vacuum the bottom once a week. If you downsize your fish you will have less work and enjoy your tank much more.

You really need to go to a good fish aquarium store and get yourself some proper advice on how to start and keep an aquarium. A good place would have told you not to keep those kind of fish together.

Alternatively, there are tons of fish websites on the internet. Start surfing and get the proper information. Go to the library and get some books about keeping pet fish. You need to be educated desperately.

Good luck.

Answer 3

It's not the bubbles, the bubbles are a good thing. Do a 50% water change today and a 25% tomorrow. Don't add any medication. What's happening right now is called the nitrogen cycle. It's the process of good bacteria growing in the filter, and unfortunately, it sucks for fish to have to live through. It involves spikes of ammonia, nitrites and nitrates, none of which are good for fish. To keep the second one alive, you are going to need to do daily water changes until the cycle is over. It's going to take a while - potentially up to three months. The most reliable way to know when it is over is to get a liquid test kit, like the API master kit. Test daily for ammonia, nitrites and nitrate. When you have 0 for ammonia and nitrites and 40ish for nitrates, do one more 50% water change, then drop down to 25% water changes once or twice a week. The cycle will be over then. Please don't buy her a second goldfish. 20 gallons is on the small side even for a single goldfish and a second goldfish will cause a dangerous increase of ammonia. If the goldfish you have a is a comet (slim body, single tail), you are going to need a tank in the region of 55 gallons+ for it eventually. If it's a fat bodied one with a double tail (a fancy goldfish) you should be ok with a 20, but they still have the potential to get to 8 inches long, depending on their species, so if it seems like it lacks swimming room, do consider upgrading to a 30 or 40 gallon. Best of luck with your fish and the nitrogen cycle! :)

Answer 4

First of all, why are you keeping gouramis with the cichlid family? The will most likely kill the gouramis after a while.

But for your filter problem, did you rinse the sponge before you placed it in your filter? That could be the cause of the problem.

~ZTM