Rivulus species affinis cylindraceus DKG1

This fish was originally acquired at the west coast weekend couple years ago. Craig McGowan was the first one in our club to mass produce this fish and I got a pair from him through one of our monthly auction. I then cranked out about two hundred of them but am not collecting babies now. I am thinking that I might have flooded the rivulus markets of the southwestern United States!

This fish is by far the easiest killie to spawn and is probably the hardiest fish that can survive in any water conditions. It can fend for itself in a community tank full of other mean fish (small cichlids) but the same may not apply to other mellow killies. Females can max out to around 1.5 inches and males to around 1.25 inches within six months.

They are not exactly colorful fish by any standard but do have a touch of yellow or blue tint on their anal and caudal fins. The blue or green spangles on the flanks are subtle and can only be seen when there is glazing light to hit them in the right direction. Other times, the male fish just carries a drably dark olive green color and the female wears a beige tone. However, this fish does have quite a bit of personality that makes up for its lack of vibrant color. The female in particular is always wary but curious of her surroundings. When I approached the fish at feeding time, she would roll her body at an angle so that she can look at me in the eye. She wasn't afraid but just wanted to be sure that I would've done no harm to her. I have never seen any fish done that before throughout my fish keeping "career". That same trait has been passed to the daughters but not to the sons.

Spawning of the fish is a no brainer. I have only seen a pair of albino garneri matched this feat only one time. The pair of fish I bought did actually spawn in the plastic bag during auction! There were about 2 dozen viable eggs in the bag. I kept those eggs in a 6 quart shoe box and found eyed up eggs in four days and then fry hatched out in fourteen days at 78F. The newly hatched out fry look more like slivers and pressed themselves on the side of the shoe box for a couple days before free swimming. I did use green water as the starting food but found that unnecessary because the fry can take BBS with gusto. Subsequent spawning was carried in a 6 quart shoe box with plenty of hornwort after the fish had been separated and conditioned with live food for a week. Spawning last for about 4 hours and I did pull the breeders out to leave the few dozen eggs for hatching with no anti-fungal medication. Leaving the breeders with the eggs is a guarantee for no eggs at all since the fish are voracious egg eaters. The same egg eating trend can be said for other rivulus in general.

This fish is a fast grower for rivulus. It reached 3/8" in 2 weeks time and is sexually matured at around 3/4" at 3 months old. I highly recommend this fish as a beginner fish because it is easy to spawn, has no special demand on water quality nor food and can live in a community environment without harassing other fish nor has itself being harassed. Don't expect this fish to become a household popular because the demand for this fish is never going to be high. There is a reason why this fish is on the conservation list.