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Otocinclus, the Wonder Cat!

The most common nuisance in a typical aquarium is the ever-abundant fiend known as algae. It can grow on your plants, blocking light and stifling growth. It grows on your glass, impeding the view through the window into a world that you’ve worked so hard to create. In short, find a surface and it will grow! Short of periodically scrubbing every inch of your aquarium, or not allowing a single glimmer of light into your tank, what can be done to ward off this tormentor? Meet your best friend and aquatic lawnmower: the Otocinclus.

The Otocinclus is a dwarf sucker-mouth catfish that only grows to be about 2 inches long. This little guy loves nothing more than to eat the algae off of your plants, glass, and other tank décor and are not known to eat your aquatic plants. They specialize in eating soft green algae; often this algae is hard to see without looking closely for it. The otocinclus will eat it before it grows too long and gets out of control. Best of all, for all they do, they're usually priced quite reasonably: anywhere from $1.99 to $5.99 each.

Peaceful tanks should find room for this little gem. Otocinclus don't have a mean bone in their body and can be housed with fry and even baby dwarf shrimp. They are at their best when they can school with others of their own kind. When stressed they will travel in a pack foraging for food. Most of the time, you'll only see this behavior when you first introduce them to your tank. Once they settle in they should not feel threatened and will school less often.

Experienced aquarists will tell you that Otocinclus are a very resilient fish. They don't often contract common illnesses that plague other fish. Their greatest weakness is not getting enough to eat during handling.

Unfortunately, Otocinclus are not spawned in aquariums very often. This means that most specimens you buy from a pet store will be wild caught. As with other wild caught sucker-mouth catfish, this makes for a perfect storm. Otocinclus are scooped up by the hundreds and transported to a warehouse where they're fasted for a few days before they are shipped out. They arrive at a wholesaler where a few hundred of them are put into a bare-bottom aquarium with no decoration and poor lighting. This means virtually no algae is grown in the tank. Algae wafers are supplied, however, the sheer number of Otocinclus is too many to feed correctly. A week or so later, they should be on their way to your local pet store. The pet store puts them into a nice tank and will attempt to keep them fed. Feeding is difficult, however, as most stores stock a couple dozen of more Otocinclus in one tank. This is odd because they wouldn't stock anywhere near that many plecostomus in the same tank.

Don't worry - even through all that stress, Otocinclus can still thrive in your aquarium. Here are a couple of simple tips that will greatly increase the survivability of your new pet:

First, make sure you have algae in the tank for them to pig out on when you get them home. After a couple weeks of poor feeding, they're plenty hungry! The best way to accomplish this is to have a quarantine tank and simply leave the light on for a week or so until you have algae growing all over the place.

Next, buy these fish the day after they come in to your pet store. This goes against conventional wisdom which says that you want to buy a fish that has been at the pet store longer to prove their longevity and lessen the shock of being transported too soon after arrival. Given that Otocinclus are typically grouped together in such abundant numbers - and are often put into tanks that can’t produce algae as fast as they can consume it - you want the stronger fish separated from the rest as soon as possible. It is sometimes difficult to know which ones have been there longest. Therefore, you’ll want to take your group of Otocinclus home and acclimate them into your quarantine tank that has been growing algae in anticipation of their arrival. This will lessen the time they spend starving as you'll already have a buffet waiting for them at home.

Otocinclus are best suited for peaceful community setups. Given their size and timid nature, they are easily out-competed for food. Make sure you have algae for them to eat before adding them to your aquarium and you’ll be amazed at the algae-control one little fish can provide. Give this dwarf catfish a try and it'll surely win you over. I know I couldn't live without them!

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