Free floating tiny dark critters in my betta fish tank

Question
Hi there,
I have a betta fish tank that I have had for about 3 years. It's a biowheel filtration system. Anyways, I noticed that the green algae in the tank was disappearing right before my eyes. On closer inspection, I saw little organisms that are the size of a pin head swimming around in the water and crawling on everything in the tank. Today I checked out the tank and the population seem to double in size overnight!  I am concerned about them and was wondering if there was anything that I could do to get rid of them?

Answer
Hi Joann,
There are many freshwater aquarium 'pests' that can invade our aquariums. Most all are harmless critters just scavenging on debris and nutrients. However, their presence may mean that the aquarium is polluted and needs more frequent water changes. Water changes are actually the best way to get rid of them. As well as their food source.

Gammarus Shrimp (AKA Scuds) and Ostracods, are two common crustaceans that get into our aquariums from aquarium plants or outside sources one way or another. Ostracods are known for multiplying very rapidly.

So the best thing you can do is start changing 30-50% of the aquarium water w/ gravel vacuuming until the critters disappear. Preventing their re-occurrence is usually just a simple matter of vacuuming the gravel more frequent and keeping a consistent good water change schedule, be careful of overfeeding as well.

I hope this helps and best of luck!
Karen~