The Otocinclus (aka dwarf suckermouth catfish or otos) are superior algae eaters. They are not clearly labeled in the fish stores as they probably should be. Compared to the the Indian/Chinese algae eaters, which are usually labeled as just "algae eaters". The Oto is said to not get aggressive and continues eating algae throughout it's life, where as the Indian/Chinese algae eaters will become aggressive and start eating other fish as they become older. I can attest to this, as I've had them before.

I purchased two Otos when I started having algae problems. They were difficult to find, only place that had them was a Pets Mart on the other side of town. They seemed to be doing well but two days ago I noticed one of them missing and yesterday both of them are missing. It's difficult to find small dead fish bodies in my tank, and Otos blend in very well with the river rocks I used. I can only assume that they are rotting away or the Bala Sharks ate them.

I've since purchased two more. One is doing very well the other has died. What gives? The other fish are doing well and chemically the water is fine.

According to the Otocinclus web site, its not uncommon to have new Otos die within the first several weeks of adding them to the tank.

There are countless reports of fishkeepers losing Otocinclus in the first few weeks of obtaining them. It doesn't seem to matter what type of tank the new fish are introduced to, they still drop like flies. Sometimes the entire group is lost, and at other times it's only a few. What's the deal?

Most hobbyists believe the trouble in keeping Otocinclus alive initially has to do with the whole capture/shipment process. Have you ever tried to net an Otocinclus among driftwood or heavily planted tanks? It's nearly impossible! Now imagine trying to catch otocinclus with a large net in a body of water filled with plants, driftwood, and rocks. That's exactly what the fish gatherers in South America are up against.

It is our belief that certain chemicals (Cyanide?) are added to the water either upstream or in a general area to slow down or temporarily paralyze these frisky little critters. The fish gatherers are then able to net them from the water in this weakened state. These chemicals could produce permanent damage to internal organs (such as the liver) and sometimes we will see hemorrhaging in the lower abdominal area in some stock.

The website also suggests that lack of algae at the fish store could cause them to starve. They suggest to look for well stocked tanks of Otos, but I have yet to find them locally (the two I bought last time were the only two in the tank).

Although Otos are cheap, it's not about the money. I really hate to have these guys die on me. I see no choice but to continue to purchase them until I can find some that will survive.