If you are a fish fanatic who is interested in observing some extremely fascinating behavior, Neetroplus nematopus would be an ideal candidate. N. nematopus are native to Central America (more specifically the Atlantic slope of Nicaragua and western Costa Rica, in the San Juan River drainage, including Lake Nicaragua and Lake Managua). Neets, as they have been nicknamed have also been known as the poor man's Tropheus for their high resemblance to Lake Tanganyika's Tropheus species. Their natural habitat resembles the goby cichlids of Lake Tanganyika with fast, turbulent waters. This should be duplicated in the aquarium environment as well. Their diet also resembles the gobies in that they like to graze off of algae and aufwuchs from rock structures. N. nematopus are pretty tolerant as far as water conditions. Be sure to keep it well oxygenated.
I acquired a group of five neets about a year ago. At the beginning, I housed these fish in a twenty high with some flame tetras (Hyphessobrycon flammeus) as dithers. Based on some reading I did, they are fairly tolerant of pH (7.0 - 8.0 pH). My water is quite hard and measured at 8.2 pH. I had lots of cave structures for them to hide in as well as some Anubias plants. I used a sponge filter set on high to resemble their native waters. After a number of months, I noticed that one of the neets was significantly larger then the others (this was the male) and also, they had paired off and took over one of the terra cotta caves I had set up. In normal coloration, males and females look the same; however, males are significantly larger then their female counterparts. Males get about 4.5 - 5 inches and have more flowing fins as well as a pointed dorsal while females are about 3-4 inches. Normally, neets have a grey colored body with a distinct black stripe in their flank. In breeding dress, they go through a color change where their body is black with a white stripe in their flank.
When I noticed that I had a pair, the female went through the color change so I was expecting to see fry soon; however, the male never went through the change so I just sat back and waited for nature to take its course. Unfortunately, nothing ever yielded from this and eventually, the female changed back to her normal colors. This transition actually occurred a couple more times in the timeframe of me keeping them in the twenty high. I then moved my group into a 29 gallon in hopes that they wanted more space. The new tank had an external biowheel filter as well as a sponge filter to replicate their native fast moving and well oxygenated water. Tank décor was minimal which included a gravel bottom, some caves and Anubias. After a few months of staying in the 29, again, there was a definite pair formed and they took over the same terra cotta cave. This time, the female went through the color change and the male stayed by her side for the entire time chasing away anyone who comes close. This went on for approximately a week and the drastic change occurred. One by one, the pair started going after the other neets. They eventually killed off the remaining three. I tried to take them out before they killed the last two, but unfortunately, I was too late. After this occurred, I started to see tiny fry venturing out of the cave. A typical spawn would be 50 or so fry; I had approximately ten or so fry. Another observation I made was that during this time, the female was always in breeding dress; however, the male never changed to breeding dress till he was in proximity of the fry. And even when he did change, it was very faint (in relation to the intensity of the female). I believe the intensity in coloration is relative to how threatened the fish feel to the predation of their young. Since there were few threats to the fry, the male never felt extremely threatened. These fish are extremely good parents. I have them housed with a single Pseudotropheus saulosi and a clown loach in the 29 gallon. The parents won't let them get anywhere near the fry and they seem to be doing fine. I feed them a variety of brine shrimp flakes, spirulina flakes as well as baby brine shrimp. According to what I've read, the parents will continue to watch over the fry for about three weeks and their protection will start to wane off. Also, neets will not spawn again if they are currently guarding a group of fry.
As far as looks, these fish are pretty mediocre, but in breeding colors, I think they are stunning to see. Also, their interesting behavior more then makes up for their looks. Neets are notorious for being very aggressive, especially towards conspecifics. Other tank mates are tolerated except during spawning, where they're chased off if they get close to their spawning site/fry.
If you are looking for a 'neet' little fish from Central America, give these guys are try. They're not a fish that's commonly available; however, they're definitely worth it when you find some.
Originally published in The Lateral Line, the official
publication of the Hill Country Cichlid Club.