Captive Care Notes: Rosyside Daces (Clinostomus, Family Cyprinidae)
Clinostomus adapt quickly to tank life and hungrily accept all standard fare. (Watch how much food they can pack into their mouths!) Be sure to keep the tank covered at all times, and be especially careful that none jump out during feeding or maintenance. Veteran tank residents associate the opening of the tank's cover with food and will literally flip out. Because of their northerly distribution, captive redside dace fare poorly if tank temperatures get too high. Keep the water below 24C (75F) and they should do just fine.
Some aquarists have noted that Rosyside Dace (Clinostomus funduloides) panic easily -- when the lights come on, for instance -- and are prone to snout infections from presumably dashing into the aquarium glass and other objects. Captive rosysides are also prone to the darkening or loss of many scales, although this does not seem to be a fatal condition. The reason for this phenomenon is not known.
The intensity of Clinostomus colors varies in the aquarium. Some specimens retain their wild colors throughout the year. Some specimens are even more colorful in the aquarium than they are in nature. And then there are specimens that refuse to color up at all. The reasons for this are probably a result of inappropriate lighting, lack of background planting, poor water quality (especially acidity), and bland food. A water change and a feeding of live blackworms may restore their crimson glow.
Many aquarists are disappointed that their Clinostomus fail to spawn, even after they've colored up quite nicely in the spring. There are two steps in getting them into breeding condition. The first step is to make sure you actually have females. Some collectors cherry pick the brightest specimens from their nets and thus end up with all males. At other times, drab colored and presumably female specimens in the wild also turn out to be males. The only sure-fire way to sex Clinostomus is to examine the snout and head for fine breeding tubercles; males have them, females don't. (Both sexes develop tubercles elsewhere on the body.)
The second step is to provide a sufficient winter, or cooling-down, period. Like many native fishes, Clinostomus spawn in response to warming water temperatures. Despite the fact that most native fish aquarists do not heat their aquaria, and may even keep them in unheated rooms or basements, water temperature doesn't always get sufficiently low to simulate the change in temperatures many temperate fishes experience in the wild. For this, an aquarium chiller is required. According to American Aquarium Fishes, Rosyside Dace can be spawned by placing a small group of males in a 30-gallon aquarium with gravel, large rocks, and a powerhead for current. Place the females in a separate tank. Keep both tanks between 13-15C (55-58F) and provide heavy feedings of mosquito larvae. After six weeks, add the females to the males' tank and gradually raise the temperature to 18C (65F). Spawning should occur within two weeks, upon which turn off the filters and remove the adults. Eggs hatch in 72-96 hours. The fry require tiny foods such as rotifers and ciliates. Redside Dace (C. elongatus) probably can be spawned in much the same manner.