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Fishmonger Newsletter

Otocinclus Article, & Construction Updates

January, 2022

Fish Store Construction Progress

The weather turned this month, so we are glad the building is dried in! The inside of the building has been painted white, which should help balance our tanks which will be painted black on all but the front pane of glass. The electrical work is making good progress. A detailed video and some pics of the progress are included below.

(That play button really improves my face!)

We are still waiting for the utility company to drop in the transformer and provide us with power, but I was able to sneak in and take a couple of pictures while the electrician had his generator going. Here’s what the inside looks like when its lit up!

There is a ton of wiring getting done…over 508 outlets for tank lighting alone, not to mention all the water treatment equipment, office outlets, and other electrical needs.

These giant concrete Legos are the custom cisterns which will collect the river water used in the fish warehouse.

Temporary concrete barriers marking the area of the creek which will be modified to supply our surface well. Don’t worry, our water use is non-consumptive and won’t hurt the creek.

A closer look at the creek…you can see ice chunks in the concrete “pond” area.

Our electrical pad has been installed and wired…this is a big step towards getting power turned on to the building.

HRV Is installed. This unit brings in fresh outside air and evacuates stale inside air without losing much heat. Sorry for the spooky pic…there were no lights installed when this pic was taken.

One of 2 high efficiency furnaces. If one goes out, the 2nd will act as a backup.

Electrical, gas, and data have all been run from the building to the street. Just waiting for the utility company to hook us up.

Featured Article

Otocinclus: Always Hungry

Written by Michael Melliere

Edited by Dan Hodnett

If you’ve seen our most recent fishroom tour video, you know that we brought in a handful of Otocinclus species in our last import order. While often overlooked as “just another community fish” or “part of your cleanup crew”, we want to take a minute to share why these are some of our favorite fish in the fishroom right now, and how you can get the most out of keeping them in your own aquariums.

Nannoptopoma sp. Orange is one of the prettiest of the Otocinclus-type catfish with their orange heads.

Affectionately referred to as “Otos,” Otocinclus are a variety of small South American schooling catfish that has become increasingly popular amongst aquarists. Unlike most Loricariids - think plecos - which tend to inhabit high current areas, Otos are primarily found in rather sluggish areas such as marginal zones where the current is dampened by bank curvature. They are often encountered in the dense vegetation occurring along margins by the bank, which they constantly graze for algae, biofilm, and other sources of nutrition. For aquarists, this means these fish are perfectly happy without extreme water movement. While they may enjoy a powerhead, a strongly bubbling sponge filter is likely all that is needed. For this reason, Otocinclus have become many aquarists’ go-to choice for planted aquascapes and other feature aquariums where a small, subtle fish can take a backseat to the overall aesthetic while maintaining the cleanliness of the tank for the aquarist. In nature, these fish can be found east of the Andes from Venezuela to Argentina. Those in the aquarium trade are often collected from the Rio Nanay, Rio Japura, and Rio Napo basins.

Hypoptopoma cf. gulare is one of the “Giant Oto” species, growing to almost 4”.

Several species of Otocinclus-type fish exist in the wild, including some that are quite beautiful. Nannoptopoma sp. Orange, Otocinclus cocama, and Hisonotus aky are all striking fish. In the trade, the "Common Oto" is often purchased for algae control. However, this trade name is used to designate any of a number of similar looking species, resulting in a great deal of confusion among hobbyists who try to identify which species they have. Often sold as the southern Brazilian Macrotocinclus affinis, the "Common Otos" in your local fish store are most likely O. macrospilus, O. vittatus, or O. vestitus. The good news is that the care for all Otos is quite similar so, no matter which species you have, it can be maintained by following a few basic needs.

Otocinclus vittatus (probably) is one of the “Common Oto” types cherished for algae control in planted aquariums.

Need #1: Constant Feeding

Because Oto’s are sold as "cleaner fish '' and "algae eaters", it seems logical to assume they will be self-sufficient in just about any tank. After all, they are small and will be able to forage for more food in the tank than they could ever want, and thus don’t need much attention or targeted feeding...right? Wrong. This is one area where we think many people fail when keeping Otocinclus. Almost all Otos are collected from the wild and are accustomed to eating algae, biofilm, and small critters which they scrape from plant leaves and other surfaces. In order to obtain enough nutrition, they graze almost constantly, day and night. During their time in the supply chain, these fish are usually deprived of adequate food. Therefore, they often arrive at fish stores underweight and in need of attention. While the algae and biofilm in a well established aquarium will give them an initial food source, a group of these highly social fish are likely to eat through the tank's "natural" food sources in short order. And, since they do best when kept in groups, food shortages can become an issue if not planned for in advance.

An attractively patterned Zebra Otocinclus grazing on wood.

What they need in order to become and remain fat and sassy is a near constant supply of food. Here's what works for us here at Dan's Fish:

For the first several days, rocks, pipes, and other hardscape which is covered with surface algae is rotated into the tank daily. This is a food source the Otos recognize and will consume eagerly. We also include an algae wafer and a coin of fresh zucchini which is sunk by impaling it on a fork. The fish won't recognize the algae wafers or zucchini as food for the first few days, but they should be in there from day one to give the fish time to become familiar with the strange new food sources. The algae wafers and zucchini are removed and replaced with fresh items before they spoil. After a few days, the Otocinclus will start eating on the algae wafers and zucchini and the algae-covered hardscape rotation can gradually be decreased until it becomes an occasional treat. This is a lot of work, but it is the best way we have found to transition these specialized surface grazers to aquarium foods. Of course, there are many veggie and biofilm based foods available which merit experimentation. As long as they are fairly water stable and don't degrade quickly, there is a good chance they will work out well.

We also find that wood helps. While not dedicated wood eaters in the sense of the Panaque plecos, Otos do enjoy the occasional chew as evidenced by the small piles of sawdust which gradually build up on the substrate when they have access to wood.

Need #2: Clean, Oxygenated Water

Earlier in this article we mentioned that in nature Otos tend to avoid habitats with super strong flow. However, that does not mean they prefer stagnant conditions. In fact, they can often be found clustering around the filter playing in the water movement. These fish appreciate current as long as it is not too strong and there are areas of refuge where they can escape it. What they do not appreciate are the ammonia and nitrite spikes and other fluctuations that plague new and/or poorly maintained aquaria. They thrive most readily in mature aquariums. Clean, well oxygenated water in a stable aquarium will go a long way towards helping them thrive long-term.

Common Otocinclus removing algae from Java Fern leaves.

Need #3: Proper Tankmates

When it comes to finding suitable tankmates, the sky's the limit. However, there are a few general guidelines to keep in mind. We ascribe to the general rule of thumb that any fish will eat any other fish that will fit in its mouth. Otos are small, spiny fish which often get anchored in the gullet of any bigger fish which try to eat them. You don't want to find your prized goldfish or cichlid dead after attempting to eat an Otocinclus, so please don't keep them with fish large enough to try and swallow them.

All the Otocinclus-type fish we have kept have been great algae eaters, including this Giant Oto.

Another thing to consider when selecting tank mates for Otos is that these fish are easily outcompeted by fast eaters. The Otocinclus are going to need to be able to graze on food constantly, and they can't do that if their tank mates consume it. We've had great luck with dedicated micro-predators such as small halfbeaks, Dario dario, Bumblebee Gobies, Sicyopus Gobies, Lentipes Gobies, Hummingbird Tetras, and the like because they are not interested in eating algae wafers or zucchini. We've also had great luck with dedicated surface dwellers like Pygmy Hatchet Fish which stay out of the Oto's way at feeding time.

Compared to the diets of many other fishes, the Oto’s food sources are somewhat lacking in nutrition, so they must feed constantly in order to stay healthy.

There are several species of Otocinclus, all of which share the characteristics mentioned to this point in this article. We currently have a few species in our inventory, ranging from “commons” to “giants” which grows to be about twice the size of standard Oto’s. We love these fish, and when they are cared for properly, we think you will too!