Hypancistrus contradens: Pretty as a Picture

Author: Ruben Lugo

Although I have always enjoyed keeping all types of fishes, from a young age I’ve always had a soft spot for catfishes. From Corydoras to Synodontis, I have always kept some type of catfish. In the last five years or so my focus has turned to the Loricariidae, the so-called plecos. Plecos come in an array of colors, patterns, and sizes. Adult sizes can range from just over an inch (2.5 cm) in length to monsters that get over 3 feet (1 meter) long. My favorites among them are from the genus Hypancistrus. The genus contains some of the most beautiful and exotic plecos available in the hobby. They are not only beautiful fish but also stay on the smaller side—perfect for someone with limited space, such as myself.

One of my favorite species is Hypancistrus contradens. Ever since I saw a picture of this species I told myself I had to acquire a group. They will always be special to me, as they were the first Hypancistrus species that I was able to breed.

Keeping Hypancistrus Contradens

H. contradens comes from Rio Ventuari and upper Rio Orinoco in Venezuela. Individuals are striking, with large white spots on a black body. They grow to only about 5 inches (12.5 cm), and a small group can be kept in a medium-size tank. Most people think of plecos as algae eaters, but Hypancistrus will not thrive if expected to eat only algae. They are omnivores with a preference for meaty foods. Any of the commercially available sinking sticks, pellets, or flakes with a higher protein content are suitable for them. They should also be fed quality frozen and live foods, especially during the spawning season. Frozen mysid shrimp, frozen bloodworms, daphnia, and live blackworms are readily accepted. They should also be fed some spirulina and vegetable- based sticks, flakes, or pellets—or even fresh vegetables once in a while, especially when they are young.

Another common misconception regarding plecos is that they will eat detritus. Not only will they not feed on detritus, they produce more waste than any other fish I have ever kept. It is very important to do regular water changes with plecos or water quality will deteriorate quickly. Hypancistrus species like warm water, and H. contradens is no exception; it should be kept at 78° to 84°F (26° to 29°C). Warmer water holds much less oxygen, and a high dissolved oxygen content is important for this fish. This is easily solved with an airstone, a powerhead (especially with a venturi intake), or with air-driven filters. This species prefers soft, acidic water but will thrive and breed in slightly alkaline water also.

Preparations for Breeding

Back in 2011 I had the opportunity to get some young, wild-caught H. contradens. I jumped on the offer and ordered six unsexed young adults. I received the fish in great condition. I had a quarantine tank ready for their arrival, and they adjusted to their new home in a few days. After six weeks of quarantine they were put into a 29-gallon (100-liter) tank equipped with two internal sponge filters and a small external hang-on-the-back (HOB) filter to create some current. I added a shallow layer of pool filter sand and mixed a small amount of crushed coral with the sand to buffer the water. Decor consisted of a few pieces of driftwood and some slate and clay caves.


It is very important to have at least one cave per male, and that there are barriers that separate them visually. I like to keep more caves than there are fish in the tank. I also provide them with different sized and shaped caves. This gives the fish options and lets them pick the cave they feel most comfortable in. If you have multiple males and only have one or two caves, the males will fight over the caves. This will result in injuries or even death to the smaller or less dominant males. Some females will also hide in the caves, so it’s a good idea to provide caves for them also.


For the next few months the fish were fed heavily and received 75 percent water changes weekly. The fish grew well and soon were sexable. The males develop “hairy” odontode growth on their pectoral fins and are also very “hairy” on the posterior part of their bodies. Females may develop some odontode growth also, but not nearly as much as males. The odontodes on the cheeks are also longer on males than on females. Unfortunately, I ended up with five males and one female—not exactly a great ratio for breeding purposes.

Spawning in Nature

In March 2012 I started simulating a dry season to see whether I could trigger them to spawn. In nature these fish come from areas that go through extreme changes in season. The water levels in the rivers are very low in the dry season. There is not much flow and food is scarce. The rainy season brings torrential downpours that cause the rivers to flood. That is when many fish species spawn. As the rivers flood, the increased flow brings an abundance of food for the adults and fry. As the water levels rise, there also are many more places for the fry to find shelter and avoid being preyed upon by larger fishes.

Spawning in the Aquarium

Trying to re-create as many of those changes in our aquariums can usually trigger the fish to spawn. The fish were in great condition, and the female was nice and plump. I let the water level drop and fed minimally every other day. I also stopped doing water changes during this time and let the temperatures climb to 86°F (30°C). Around the end of the third week, we had storms heading our way. Fish sense the drop in atmospheric pressure when there is a low pressure system in the area. I always try to time the start of my “rainy season” with an oncoming storm. The evening before the thunderstorms I did a 90 percent water change with water that was about 8°F (-13°C) cooler than the tank water.

Effort Pays Off

I started feeding heavily with frozen bloodworms, blackworms, and mysid shrimp. A powerhead was also added to the tank at this time to create lots more flow. I did not see any spawning behavior, so I continued doing 50 percent daily water changes with cooler water for the next two days, plus heavy feedings. On the third day I started to notice some spawning behavior. That evening one of the males had the female trapped in his cave. The next morning the female was back in her usual spot under a piece of driftwood. I excitedly grabbed a flashlight and checked the cave where the male had had her trapped. At first I could not see anything because he was far back in the cave. But when he moved slightly I could see eggs!

After the eggs are laid, the female leaves the cave, and the male takes care of the eggs and the fry. The male uses his pectoral and anal fins to fan the eggs and keep water moving around the egg mass. Although I wanted to check on the eggs every chance I had, I had to control my excitement and not flash a light on the male any more. This can disturb the male and sometimes results in eaten eggs, or the eggs will be abandoned or kicked out of the cave. I let him be and would just visually check on him daily.

Caring for the Fry

At about the week mark, my curiosity got the best of me and I grabbed my flashlight to check inside the cave again. The male was trying his best to block my view, but I was able to see a few wrigglers in the cave. After about two weeks the fry had completely absorbed their yolk sacs and slowly started venturing out of the cave.

At this point they needed to be fed. Baby brine shrimp, daphnia, rotifers, and any flake or crumbled regular aquarium food are readily eaten. I stay away from feeding the young ones bloodworms until they are about 2 inches (5 cm), and even at that size I chop up the bloodworms for them, because I have had them choke on bloodworms when they are young. The fry can be moved to their own tank for growing, or they can be kept with the adults. I have always kept the young ones with the breeding group until they reach about 1½ inches (3.75 cm), and I have never had any problems with the adults eating or killing the fry.

Hypancistrus contradens individuals, in general, are slow growers, but regular water changes and good food help the juveniles grow quickly. My group of fish continues to breed for me, and they give me about three or four spawns per year. The male that was breeding the first year or so did an excellent job of raising the fry. Unfortunately, he lost his alpha status, and now the male that is breeding is not as good a father. He kicks out some or all of the eggs. When this happens, the fry can be raised artificially using an egg tumbler or a fry net with an airstone. I prefer to use an egg tumbler and have had great success raising fry from uncooperative males.

This year I plan on holding back a few juveniles to grow out and start another breeding group. If you have an extra tank lying around, give them a try. They are not difficult to keep or breed, and if kept in optimal conditions will reward you with fry for many years.