Pseudogastromyzon cheni activity.

[Martin Thoene]

I'm expecting some breeding activity soon in the big River-Tank. There's a bunch of male cheni showing sexually mature tubercules and clearly judging by this guy's dorsal there's been some scrapping going on:




The first pictures are of a fish from my original stock family line, noted for the bold markings and good dorsal colour. This fish is one of the newer fish that I got from Harold. Not quite so nicely marked and in some cases, these fish don't even have any red in the dorsal. This one does:




He's a gnarly little dude though. You can imagine being another one knockin' noggins with him....ouch!

Martin.

[Jim Powers]

Must be something in the air...or water. Mine spawned this afternoon.
Those are great shots. I don't think I have seen such a good shot of the tubercles before. They are certainly "in the mood for love". I have definately never seen such battle damage before, either.
The difference in markings is interesting, too. Its basically the reverse of mine. My original batch was not as well marked as the last pair I bought. However, the new female doesn't have as much dorsal fin color as the originals and the new male.

[NancyD]

Do the tubercles only show so much when the males are feeling "frisky" or are they always as visible once they hit maturity? Nice pics.
Nancy

[Martin Thoene]

Pretty much always visible Nancy. Females have small ones too. But in sexually active males they are enlarged and generally most prominent in the dominant male in aquaria conditions certainly.

Martin.

[LES..]

Hi All,

I have been meaning to ask this for a while now and it seems appropriate to this thread. Is it ethical to keep my p. cheni fry and create a shallow gene pool?

Martin, you mention that some of your fish are from your "original stock family" is it enough to simply introduce new fish from outside sources to replace any natural losses or should i be actively looking to find new homes for the fry to prevent inbreeding?

All advice greatfully received.

[Martin Thoene]

Good question Les. With all species of fish that are bred in captivity we run the risk of weakening the genes by inbreeding over time. My current fish are probably at least 6th generation. No exact idea on that just guessing, but I have noticed some degredation in overall appearance from the original stock and there seems to be a reduction in longevity, but that might possibly be caused by captive diet or something else.
I got the other fish because they were there, rather than as a direct attempt at bringing in outside genes. My LFS got them in as something else. The fish live in a mixed community with other fish that will eat the eggs or fry. Hence I've had no babies in ages.
Only way to keep fry alive is to keep the fish in a mixed tank of other sucker-bodied fish or to run a species tank, much as I'm doing with my Sewellia. Should they spawn, there's no way I'm risking fry predation by other species.

Your cheni will only produce relatively small numbers of babies even if there's a high survival rate, and the growth rate doesn't make them a great proposition for selling for profit. Not compared to other species of aquarium fish that is. I would not worry too much about inbreeding.

Martin.

Martin.