Parasites?

Question
Hi, I am hoping you can help me with a question regarding my 48 gal fresh water tank. I have four Large Silver dollars in it at this time and I do the 25% water change on a normal basis and about 2 months ago I defeated an ich breakout. The tank has been doing well and I was considering adding a variety of fish with them. Tonight I was checking on my lovely fish and cleaning the side with magnets and when I got to the bottom it seemed to have stirred up these creepy critters living in the gravel. They are about as skinny as a hair follicle and about an 1/8" long, they are clearish white and swim like squirmy eels, very erratic in movement. They do not seem to be attached to my fish and they go back in the gravel when there is no movement. Are these parasites, or could they possibly be something from the blood worms I have fed them in the past, both living and sometimes frozen? Also I have noticed the smaller of my silver dollars is not so silver and pretty anymore he is getting a striped look to him like a tiger, is this an illness? If everything is ok can you recommend a good type of fish I can add in with these guys? Thanks in advance and I look forward to hearing from you soon. Julia

Answer
Hi Julia,
No worries, I believe for certain they are what's called "Planaria" and these creatures are very common in aquariums. They are harmless scavengers, feeding on excess waste, detritus, and food. Their large numbers indicate that the aquarium needs more frequent gravel vacuuming/water changes. Planaria are most often occurring in cichlid tanks, goldfish tanks and other aquariums that contain fish that produce a large amount of waste. And therefor are more prone to planaria overpopulations.

The best thing you can do is to start changing 30-50% of the water with thorough gravel vacuuming each time for several days or until the planaria population diminishes and most likely will disappear completely with persistence.

They usually don't come back often unless the tank has collected too much waste again in the gravel bed, ect... and the planaria now have the overabundance of nutrients to once again fuel their overpopulation.

As far as the striped Silver Dollar... I've never heard of them developing stripes. I do know many fish will develop stripes if they are under stress, are being aggressive, or even if they are frightened. See if he might be getting bullied by the others. And with the water changes, he might also improve.

With Tankmates for Silver dollars. Since they are peaceful, they generally get along with many different types of fish that are too big to be eaten and similar in temperament to their type. Larger tetras such as those the size of Black skirts would be great. As would rainbows, giant danios, Barbs, large livebearers, cory catfish, plecos, small/medium reasonably calm cichlids, ect...

I hope this helps!
Karen~