Sterlet Sick? Acipenserids; not for aquarium use
Hell Wet Webbers...My name is Peter Sewchok. You have helped me with
several questions through the years.
I just purchased a very young, very small Sterlet (cousin of the larger
Sturgeons for those reading). It is roughly an inch long, and I have it
in a 40 gallon breeder
with mini-Amazon sword plants, some Cabomba, and a fine sand bottom.
The Sterlet has started swimming like he is crazy; loops, upside down,
etc. I know that they swim in odd patterns, but the past two days I
found him lying on his back in the sand bed.
<I see... is he resting, or are his gill covers moving rapidly, as
if he's panting?>
I have two large Bio-wheels in the tank and a powerhead for a current.
The nitrites are zeroed, and the nitrates range from very small to zero
before water changes. I hope that he is not near death. I am feeding
high-protein flake food as he seemed to ignore the black worms and
<I'd be offering a more varied diet, in particularly with
wet-frozen wormy things: bloodworms, Tubifex, etc.>
Water is cool.
<By which, do you mean the aquarium is unheated, or that there's
a chiller attached? Optimal water temperature is about 14 degrees C;
anything above 18 C is essentially lethal. Like a lot of Eurasian fish
(such as Koi and Goldfish) they prefer water that is hard and alkaline,
so avoid soft, acidic conditions. Kept cool and in the right water,
this fish is actually quite hardy, though like a lot of
"primitive" fish it is quite possibly intolerant of copper-
and formalin-based medications.>
Any help? I know Sterlets get huuuge...his retirement home is a large
pound. I lost two other larger Sterlets in a different tank; one leapt
out despite it's hood, the other managed to mangle itself fatally
on a powerhead. Please send any advice that you can: I love Sturgeons,
sharks, and rays. To me, the Sterlet is much like a TRUE freshwater
shark; basically the closet we will probably ever see in the hobby.
<More specifically, Sturgeons retain some primitive characteristics
that sharks also possess, such as the heterocercal tail. Oddly enough,
of all the living fishes, they're most closely related to Bichirs,
though the two groups diverged sometime during the Triassic
I just also wanted to post a final note: Despite what one might read on
the Net, Sterlets / Sturgeons are very tricky fish to keep...up there
with salt Catsharks and freshwater rays.
<Like a lot of European fish, they're "tricky" when
kept too warm; unlike the Continental United States, which experiences
long, hot summers even in the northern temperate zone, Europe has a
more maritime climate and summers are rarely particularly hot. So
European fish tend to be adapted to relatively cool water, and compared
with North American fish like Darters and Sunfish, they're often
less tolerant of indoor temperatures. There are plenty of exceptions of
course, but Sturgeons aren't among them. It's absolutely
critical they're kept cool and provided with water that has a
massive rate of turnover and lots of oxygen. I'd be aiming for a
turnover rated 8-10 times the volume of the tank (i.e., a 320-400
gallons per hour filter for a 40 gallon tank) and using a venturi jet
return to keep the water well agitated.>
Think before you try them.
<Weirdly, they're not infrequently sold here in England as pond
fish; they can do well in big, deep, well-filtered ponds, but you
don't see them much!>
Despite years in the hobby (15+), I am starting to believe that
Sterlets are best left in the river.
<Certainly true for the larger species; Sterlets and the
"Bester" (a Sterlet/Beluga hybrid) are farmed, so the ones
you see in pet shops are most likely hatchlings from fish farms. As
such, they're worth experimenting with if you're an advanced
hobbyist interested in big, coldwater species.>
Re: Sterlet Sick? -- 07/01/09
Thanks for the response. The Sterlets that I have worked with before
seemed to filter feed some of the time like their cousins the
Paddlefish, and they largely ignored frozen foods.
<Sturgeons aren't filter feeders, they're predators, feeding
primarily on insect larvae and crustaceans when small, and small fish
when mature. They certainly don't need feeder fish in captivity,
and as you probably know there are multiple compelling reasons not to
use feeder fish anyway. But they certainly should receive a varied diet
of meaty foods: earthworms, small crayfish, snails, mussels, prawns,
etc. Once settled, they usually take carnivore pellets, but they're
not "scavengers" as such.>
This guy is responding to some freeze dried bloodworms that I bought
today (Omega 1), and still really seems to like the protein flakes.
<Dried foods are insanely overpriced for what they are, and many
fish reject them. They can also cause constipation if used continually.
So get yourself some wet-frozen foods: bloodworms, krill, mysis,
Tubifex, etc. and use these as the staples, along with a bag of mixed
frozen food from the supermarket (here in England at least, typically
mussels, squid, and prawns).>
I don't think he likes the blackworms, which is strange because
delicate fish ( ie stingrays) seem to love them.
<None of my fish like freeze-dried anything. Never have, in 25+
years of keeping fish!>
The weird swimming is still going on occasionally, and I'm
wondering if maybe this is just the way some small sturgeon swim. The
water turnover should be fine - Two Marine Land 800's and a sand
level powerhead. I find it odd that Sterlets are used in ponds in
Europe...wouldn't a pond with driftwood and plants present a
softwater situation like one might find in a bog or in the Amazon?
<Not really, depends on the water chemistry, circulation,
To answer your question about the temp in the tank: no heater, no
Chillers are really hard to come by here in Pittsburgh, PA.
<Try mail order; widely used by marine aquarists.>
The room is cool - air temp 67. That's basically year round.
<That's your problem. Too warm. An old "mini bar"
fridge, with a couple holes drilled in the case, and a couple metres of
outlet pipes from a robust external canister filter does the job
I don't have a thermometer in this particular tank. Lighting is
Tankmates are a half-inch long mad tom catfish that I rescued from the
feeder tank of a local
FS, and a Hillstream loach / china loach / china Pleco (erro). I'm
going to add an air stone for extra O. I also wanted to ask about these
new filters that use a chemical process to remove Nitrate Matter...are
they the real deal?
<Don't do anything water changes won't do, and certainly
don't remove the need for regular water changes. Cheers,
STERLET SICK UPDATE 7/3/09
Hi again. I made a "cheap chiller" by running a tube from the
freezer of a small fridge from college. It's a little cooler in
there now. Sterlet is still a loopy little thing. He ignores frozen
bloodworms, is eating frozen brine from Oregon Foods, and the
freeze-dried bloodworms. No idea why...maybe they smell salty?
<Maybe. In any case, just keep varying the foods. Freeze-dried
bloodworms (indeed, freeze-dried invertebrates generally) aren't an
acceptable long-term food. They're too expensive and too prone to
causing constipation, which in turn increases the risks of bacterial
infections. So be creative; I'd recommend wet-frozen krill as being
especially nutritious, and these should be taken readily enough by
Sturgeons, as should wet-frozen Mysis and chopped cockle.>
He isn't lying on his back anymore or swimming upside down as much.
I think he might be eating those annoying little black pond snails,
too...there some empty shells in there now...unless they are eating
<Yes, they eat snails.>
I would think that the tiny bullhead type catfish that lives in the
tank would probably eat them whole rather than shelling them, but I
Can you recommend some other coldwater companions?
<Most anything non-aggressive that enjoys the same cold conditions;
Sturgeons are predatory of course, so small minnows and such will
likely be eaten, but otherwise things like Carp, Tench and so on work
well. Avoid territorial fish like Sunfish, since the constantly active
Sturgeon will repeatedly invade their territories, leading to
Benghana Bengri maybe?
<I have no idea what these are, and more surprisingly perhaps, nor
I was also wondering if you guys could help me find info about
freshwater pipe fish. I have found them available, but have no idea how
to set up a tank for them. I would guess it would be similar to a
seahorse tank, but I don't want to guess.
<Yes, they're very like *wild* as opposed to tank-bred
Seahorses. They are notoriously difficult to feed, and generally take
only live foods, primarily Daphnia in the case of the midwater Pipefish
(such as Microphis and Syngnathus spp.) and Daphnia plus insect larvae
such as bloodworms in the case of the species that like to crawl about
on the bottom as well (as in the case of Enneacampus spp.). The bigger
species will take very small livebearer fry as well, such as newborn
Guppy fry. So it's not worth keeping them unless you have access to
a constant supply of live foods, such as garden pond. Now, another key
problem with Pipefish is that retailers generally do not know what
species they are selling. Unless you have a Latin name, be critical of
anyone telling you it's a "freshwater pipefish"; the
reality is that many so-called freshwater species in the trade are
brackish water species, and will need at-least slightly brackish (SG
1.003-1.005 at 25 C) conditions to do well. Do see here:
Re: Sterlet Sick? - 07/03/09
Hi yet again...Thank you so much for all of your help with my Sterlet.
He thanks you, too. The fish that I mentioned in my previous mail that
you couldn't find on Google is actually called Bangana behri. I
spelled it incorrectly last time.
It's a large, strange carp. From what I am reading, probably too
<If in doubt, Fishbase!
http://www.fishbase.org/summary/speciessummary.php?id=16212Yes, at 60
cm, this would be of questionable value as an aquarium fish, let alone
a companion for a *coldwater* fish like a Sturgeon. Though best kept
alone, in a sufficiently large aquarium, coldwater carp-type fish
around 20-30 cm in length would make good companions. Hardy Goldfish,
young Koi, Tench and so on are all obvious choices.>
I bought some Mysis today, and some krill. We'll try those. Thanks
<Good luck, Neale.>
Re: Sterlet Sick? 7/5/09
Hi crew. Just wanted to thank you, Neale. Sterlet seems much healthier
/ happier. Swimming laps around tank like a "normal" fish,
playing in jetstream bubbles, resting in sand much of the day. No more
gills moving normally.
<Ah, this is good news! Glad to hear the chiller has made a
difference; usually does, and especially so in summer. Happy