A Great Question

By David L Banks Jr, TFCB

TFCB September, 2011 

I recently received this question from someone I had talked to about fish a few months ago.  I thought it would make a good quick article, so here it is.




tank has been good with 4 fancy goldfish and filter, but now algae is accumulating on bottom gravel, bamboo plant (wife got it), and windows. We added a "Dory" catfish for bottom maintenance, but we had thought it did algae too.

Needless to say it isn't cleaning up the algae, but he's living nice with the fancy goldfish.


What should I add, 

Chinese algae catfish or the primitive looking p---------------- catfish for algae maintenance?  Or what is the best way to maintain the algae itself?  THANK YOU.




And here was my initial response:




Important question!!!  J


Algae will grow if the tank has too much light, too many nutrients ( ie fish waste, or over feeding ) or both.  Most tanks will get a little, but if you are getting a lot, it is best to solve the problem.  30-50% water changes weekly will help to keep the nutrients down.  Only feed the fish what they will eat in 5 minutes, you can cut that down for a few weeks to see if that helps too.  Light only needs to be on 10-12 hours a day at most.  If the tank is getting direct sunlight, that can definitely contribute.


The other option is getting fish that eat algae.  Cory catfish( I assume thatís what you have, never heard of ďdoryĒ) are great little catfish, but donít eat algae.  Chinese algae eaters only eat algae when they are small, and they get very large, 6+ inches, and get more aggressive as they get larger.  Plecos in general also get very large, some over 2 feet.  They are also good at eating algae when they are small, but as they grow require more food and can contribute to algae problems in a small tank.


There are several plecos that stay small and are good algae eaters.  Ancistrus or busy nosed plecos are my favorite, they only get to about 4 inches and eat lots of algae, you usually need to feed them in addition to them eating algae.  Clown plecos also stay small, only 3 inches, but are not quite as good at eating algae.  Some of the nice expensive plecos also stay small, but many are not algae eaters at all.


Temp is also a concern, but cory catfish can usually take cooler temps, and Ancistrus seem to do ok down to about 65 although they probably like warmer temps in low 70ís. 


Hope that helps. 





Then it occurred to me that snails would also be a good option, so here is my follow-up email:


Another good option might be snails.  Not sure of temperature requirements for them, so you might need to check on that.  Apple or Mystery snails would be good, and I have often seen them in tanks with goldfish.  There are other snails too, but apple and mystery snails are pretty easy to control, others can have population explosions and end up adding to tank maintenance problems.