OTO, Midget Sucker-mouth Catfish. Part of a large family of Loricariidae, the Otocinclus is one of the smallest. It is usually tan with a black peppered body. Found in rapidly moving rivers.
Oto catfish grows up to 5cm, which makes it suitable for smaller aquariums. Otos should be kept in planted tanks only! They do much better if kept as a smaller shoal. Oto is the best plant leaf cleaner and will remove almost all algae from it without damaging the leaf. It will ignore the grown algae but will eat young algal growth and by doing that will keep the algae very low. Like all catfish, even this one likes the presence of bog-wood, so adding one piece to the aquarium would be a good idea. If there is no sufficient algae in aquarium Otos should be fed with blanched zucchini once a week. Boiled for 2 minutes and cooled down before feeding. Place the zucchini on the bottom or even better on the piece of bog-wood where the Oto will come readily and notice the vegetable. Do not leave the zucchini for longer then two days inside the tank and not shorter then a day. Its been known that Otos will ignore sinking catfish tablets and algae wafers, and will ignore most of other vegetables like lettuce, spinach, cucumber, etc. Zucchini is the best proven feeding choice. Some aquarists farm algae and than introduce them as Oto food. Its been known that Otos relish Brown algae (diatoms). One of the best ways to insure that Otos will have sufficient algae is to keep one Oto per approximately 60-70 liters. After observing the algae in your tank for a week you will get the answer for, do you need to add more Otos? How to know does my Oto have sufficient algae? Keep close eye on their stomachs. Round bellies are a good sign of algae sufficiency. It is good not to clean all your aquarium glass at once since they will eat the algae off the glass. Otos should be kept with smaller/calmer fish. They like to rest on broad plant leaves and bog-wood rather than gravel.
The Otos can be difficult to acclimate to the home aquarium, but if provided with correct water conditions and there is some green food they will be fine. The set up should be well established with a sand or gravel substrate. Densely planted with live plants. An established algal growth is essential. While they will take flake food and sinking pellets the natural greens are needed to provide proper health. If no algae is available they will eat the softer bodied plants. Provide good water circulation and filtering. Best keep in groups. The actual number will vary upon the tank size. Compatible with most fish except the larger predatory species. Otos live up to 5 years. They need a pH around 7. Water temperature should be around 25 'C.