Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Cleaner fish

Sailfin pleco
Sailfin pleco

Algae eaters

So you have passed the first hurdle and cycled your tank. Then after just a couple more weeks a new problem - Algae.

You take yourself off to the fish store and enquire about this new problem and the nice man in the shop sells you a fish which is an algae eater.

Below is a list of fish which make great algae eaters and will keep your aquarium free of algae.

You'll probably have noticed by now that it isn't a very long list!!! This is because such fish don't actually exist. Sure, there are some fish which will nibble at algae when young, and there are fish with large sucker mouths which APPEAR to be scraping algae from the rocks but the truth is that all these fish will very quickly forget about algae when offered a much higher quality diet in the form of flake, pelleted, freeze-dried, frozen or live food.

It gets worse. Quite a lot of totally unsuitable fish are sold to people with a small community tank under the general heading of 'pleco' which could actually be any one of a number of different species most of which grow quite big, too big in fact for most community tanks. With good care some will reach in excess of 45cm (18in) and as adults they won't even look at algae never mind eat the stuff. Many of them also become increasingly belligerent as they grow.

In order to control algae in a community tank:

  • Keep the lighting period to a time when you are there to view the fish. Don't just automatically turn the lights on in the morning and leave them on all day. The fish really won't mind at all.
  • Keep on top of water changes and keep the substrate clean.
  • Use an algae magnet on the front glass and leave a slight covering of algae on stones ect (as you will find in nature), as long as the algae doesn't become unsightly learn to live with it because you'll never achieve a completely sterile 100% algae free aquarium.


Unlike algae eaters, scavengers do exist, sort of. But lets not get carried away here. Bottom feeding fish will pick up the food which gets to the floor and may be overlooked by some other species. In this respect bottom feeding fish will help to keep the tank clean.

BUT they won't eat any dirt and they won't keep the gravel or the tank clean for you. That is most definitely your job as a fish keeper. It is also worth bearing in mind that bottom feeding fish need a full and varied diet just like any other fish. Don't just assume that they are getting enough food by picking up the scraps which fall to the floor. There is plenty of variety of sinking food available for the bottom living species so please use it occasionally.


Forget about trying to find a good algae eater.

It's YOUR job as a fish keeper to keep the tank in good order, not the fishes in your care. 

'Traditional' Algae eating fish

Siamese flying fox,
Crossocheilus siamensis.
This fish has legendary status after being listed as the best algae eater in a very popular aquarium book. ?In truth it is no better than any other of the flying foxes or sharks. In my own experience the red tailed black shark is better but even that won't clear your tank of algae.

Hypostomus plecostomus & others.

Only juveniles will make even a token effort to eat algae, until they get a taste for the better food on offer. They are capable of growing to a large size (18in) and they become increasingly aggressive. Despite all this they remain very popular 'algae eaters'.

Bristle nose pleco,
Ancistrus spp

Unlike the above fish this genus actually does eat algae or it eats some types of algae. But there are many many species of algae and if one species is controlled another will grow to fill the niche. So after an initial success the problem will return with a different kind of algae which the  won't touch. Most Ancistrus are quite safe in a community tank and they don't grow too large.

Chinese algae eater,
Gyrinocheilus aymonieri,

Also known as the sucking loach. This is quite possibly the worst of the bunch. The Chinese algae eater doesn't come from China, it isn't a loach and it doesn't eat algae. They can grow to 10 in  and they are extremely aggressive. There is absolutely nothing to recommend this fish.