Originally Posted by poolman84
Well I'm back from the shop with 3 more cory's and no more serpae, ironically enough. They had all been bought up before I got there this morning. So lets get to the bottom line. Should I keep these 4 serpae and see if they settle down? What other species of fish would you suggest Byron? I know that I wanted tetra, and when I first purchased the serpae, which were erroneously suggested by the shop keeper for my tank, I thought I was all good. I do not want to overload my tank that's for sure.
In my view the four serpae will act according to their natural instincts until they die or are so stressed they can't. There is ample evidence as to the "expected" behaviour of this species, and while there are always exceptions the programming is still in the fish and can be induced by any number of factors, such as stress from too few fish, stress from too small a tank, stress from inappropriate water parameters and quality, etc.
During the interval here I checked one of my trusted sites on this fish, and the minimum tank size recommended was 20 gallons and minimum 30 inches length. I would not compound the problem with more serpae in a 10g, and the four you have will obviously continue their behaviours because it is their nature. If the store will exchange, fine.
You want tetras; there are a couple other species very similar to the serpae, so much so that distinguishing them can be tricky, and I suspect some of these others are often sold as "serpae." But in your case unfortunately, you obviously got the real thing. The true serpae is scientifically known as Hyphessobrycon eques; this fish alone has gone through 5 name changes, being placed in 4 different genera before now recognized in Hyphessobrycon. This is likely to change again, as this genus and the closely related and near-identical Hemmigrammus [the fish in these two genera are identical except for the scaled caudal fin and base in Hyphessobrycon] have been catch-alls for many new species that are slowly being reclassified. Gery (1977) determined that the scientific name for most of the species in Hyphessobrycon was incorrect, but a full review of the several hundred species is needed to sort this out, and this is actually underway.
One similar-looking species is Hyphessobrycon callistus; however, this species is now believed to be a synonym for H. eques. H. serpae itself is another. Given this confusion, it may be best to avoid these "similar" species.
Some suggestions for similar looking fish would be the red phantom tetra, Hyphessobrycon sweglesi [photo attached]. It is identical to the black phantom except in colouration. They have a fascinating interaction when in a group of 6, the males will constantly display and challenge each other, flaring out their fins and sidling up to each other, but never do they attack or harass each other. They would be ideal with your group of corys in a planted tank. They are not overly-active swimmers, mine are in a group of 12 in a 115g tank and even with all that space they are always together in smaller groups of 2, 3 or 4 among the plants, mid-tank. I have the Blacks.
Then there are the "rosy" species in Hyphessobrycon. H. bentosi, H. bentosi rosaceous, H. robertsi. The latter is not a true valid scientific name but commonly used for this absolutely beautiful tetra that was once thought to be a natural hybrid but Gery (1977) [and Zarske & Gery (1997)]determined it is a valid distinct species; it has not, to my knowledge, been officially named yet. I have a group of 7 along with 6 H. bentosi rosaceous and they are perhaps the most beautiful of all the similar species. I'm attaching a photo of two males though it does not do this fish justice; during displays and spawning (which occurs regularly in my tank) the fish turns a dark ruby red, almost becomming black, with the white fin tips sparkling. The dorsal fin of the male bends back over the fish and extends half way down the body and tail, and when the male spreads this fin to entice a female it is a sight to behold. A group of six in a planted 10g would work, with good maintenance (weekly pwc of 40-50%).
This should give you some ideas to start.