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Re: Rivulus

Hello killietalk,

        A couple of questions on some Rivulus (expected at the Chicago
show)
were e-mailed my way this evening. I don't feel real confident with my
responses. Corrections and additions would be gratefully welcomed.

        Included are some introductory comments, the correspondant's
queries
and a few responses to his questions. Please let me now where I have
erred (on the Rivulus that is...)

>       I went back to the Huber book, Review of Rivulus: Ecobiology -
> Relationships and stirred a few personal memories of a couple of those
> fish....
>
>      By the way, in converation with another killifriend, he contended that, with
> the exception of a couple of killies which he has not been successful
> with, that there is no "hard" killifish. However having said that, he
> will add that any killie is easy if a person recreates their  diet,
> water chemistry and temperature and shelter/tank space parameters. In
> other words, whatever environmental conditions necessary to get them to
> reproduce. Well that is all one has to do to get highland gorillas to
> reproduce too!
>
>         Your "easy" and "hard" are in reference (I would guess) to how different
> their care is from typical livebearers in the aquarium trade. And if
> that is the context that you are using, than I believe that my buddy is
> mistaken in saying that there are almost no difficult killies. Granting
> his point that lots of fishes, initially characterized as almost
> impossible to breed, have been much easier to breed when we figure out
> their "code" of requirements, there are still fish that are not really
> convenient (ie easy) to breed. I have already separated my theirryi
> until after the show because the male was pummeling her!
>
> 
>
> > With 1 being easy and 4 hard (i.e.. obscurus), where would you place
> > R.paryagi, R.belem R. chucunaque, R. isthmensis and R. geayi. We have
> > successfully done Xiphidius, both in a permanent set up and the mop
> > method.

> > Would the five Rivs above be in the same difficulty range?

>         I would suggest (speculating some) that the five Rivulus will have
> slightly different needs in terms of size of quarters and water > chemistry. All are probably from the same part of South
> America, but the Guyana Shield and lower Amazon have some differences > too. Even with two species from much the same place, one may be
> more easily spawned in tap water and the other will need water with less
> mineral content.
>
>         By the way, those are not all species names. You should refer to Riv.
> sp. paryagi meaning "Rivulus species from Paryagi" (whereever that is).
> It may be a new species or just not identified from the descriptions
> available. I know nothing about it.
>
>         Likewise Riv. sp. Belem is a Rivulus from the area of Belem, the port
> city in the lower Amazon, near the Atlantic ocean. Curiously both R.
> strigatus (considered a local variant of geryi by Huber) and R.
> urophthalmus are from that area. Strigatus, a dwarf jewel, has a
> reputation for needing live food and soft water. I may have been among the
> last in the early 90s to have females among the fry of that species (my
> water gets old and very acidic sometimes). Unfortunately I sent the last
> female off in trade and never heard from the correspondant again.
>
>         I once picked up geryi at an AKA convention fish sale room (for $35 and
> felt that I got a bargain). When I got them home the male immediately
> died. They were neat and their pattern was not exactly the same as the
> "strigatus". If strigatus, dibaphus and geayi are all one species, there
> seems to be a wide geographic range and slight local variants in color pattern. In the meantimes, keep
> the strains separate and remember the locations!
>
>         If you have been doing well with xiphideus (that also means you are
> doing frequent water changes) you should be able to do ok with the
> geryi. Their rarity in the hobby does suggest some difficulties.
>
>         The fish which the Riv. sp. Belem probably is, is urophthalmus, a BDR (Big
> Dumb Rivulus) which has been in the hobby off and on for 90 years. It
> has a reputation (if it doesn't fall victum to terminal dehydration) of
> being a fairly easy fish to reproduce. It also seems to have local color
> varieties. My use of BDR is a mark of affection BTW.
>
>         Isthmensis, a fairly large Rivulus, has both highland and lowland
> forms. Mine were obliging egg layers. The highlanders should be five or
> so degrees cooler than the lowlander or in the low 70s F. according to
> Dan Fromme. Theirs is a neat color pattern.
>
>         The real Riv. chucunaque (from Panama) looks a lot like our old Columbian Riv. magdalenae
> (milesi in the older literature). It is not too far removed from it
> geographically. Magdalenae is "easy" to raise assuming the tank is
> covered. I have had a strain of that fish, mostly in planted tanks, for
> 25 years. I would speculate that this other species could be kept in a
> similar manner.
>
>         I would love to forward this to Wim, but he is undoubtedly busy
> packing a ton of fish. You will get a chance to ask him this weekend. In the meantime,
> prepare as many empty tanks as you can and be prepared to encounter
> several Rivulus nuts in conversation and at the auction.
>
>                         All the best!
>
>                         Scott
>
> PS. I will post a version of this to the killie lists to see if I have
> B.S.ed you too badly.