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Re: Re: Otos in love and other sordid tales [OT]
>Can you describe other tank parameters like temperature,
>amount of water circulation, pH, etc? That's so neat,
>having them breed in your tank!
I think so too. I've had other fish spawn, but this is the first time any
catfish I've kept has spawned successfully. And it's the first egg
depositor I've had spawn. It's a new world for me. And the fact that it's
otos makes it that much better. It's like winning a bonus prize. That is
if I can sustain the fry long enough for them to grow out. And I think
I'll have another chance. One time might be a fluke, but three times seems
promising for the future.
Anyway, I set the 20H up about 8 months ago. It's a simple setup. The
only equipment other than lights are an Eheim 2008 internal filter, a 100W
Tronic heater, and DIY CO2 via yeast. The Eheim is centered on the side
glass and the outflow runs the entire length of the tank disturbing, but
not breaking, the water's surface as it goes. Surface film is zero due to
this. The flow rate is just enough to bounce water off the opposite side
and back to the filter. Evaporation is virtually nonexistent because of an
All-Glass "Versa-top" that I modified -- I replaced the back glass and
plastic strip with a wider glass piece with notched corners for hoses,
cords, and ventilation. It also helps keep the temp remarkably
stable. There's about 3.5cm (1 3/8") airspace between the water and the
Here are details on the water and maintenance:
Net volume: 65 liters (17gal)
Hardness: 6 dGH
Alkalinity: 5 dKH
pH: 6.7 - 6.9 (~7.3 if CO2 goes flat)
Temp: 24.5'C (76.1'F) by mercury thermometer
Filter flow rate: ~265 liters/hr (70.0 gal/hr) -- 4 X net volume
I change about 40% of the net volume -- 27 liters (7.1gal) to be exact --
once a week and squeeze the filter sponge out in the wastewater every
time. I always use tap water and I add a conditioner that eliminates
chlorine and binds heavy metals. Ammonia is not a problem since my local
water provider still uses chlorine and not chloramine. I draw 50 gallons
at a time and let it sit in a plastic tub for a week before I use it (I've
got two tubs that I cycle). Maybe it's superstitious overkill to let the
water sit since I use a conditioner, but old habits die hard and it seems
to agree with the animals and plants well enough.
As I mentioned in my first post, this tank is barren of visible mat algae
and has been for 6 months, so I feel the need to feed the otos. I feed
Nutri Fin Max tropical or spirulina flake once a day. I don't feed much,
just a pinch. I do make sure there's enough so the shrimp can't hog it
all. I store the can in the fridge so the flakes stays as fresh as
possible. Also, the substrate has soil which supports abundant micro fauna
and micro flora. There's all kinds of little critters in this tank and I'm
sure they supplement the otos diet. Otherwise, I'd feed them twice a day
and add a live food like microworms (nematodes) to their diet. There's
wood in the tank, so their cellulose (fiber) needs are covered.
______Odds and Ends_______
The fry numbered 3, 5, 6 in each respective batch. That's as many
individuals as I could verify anyway.
I have a light setup that simulates a 1-hour dawn and dusk period. The
regular, full-on photoperiod is 12 hours. The otos seem to like it. The
behavior I've witnessed took place during the normal period, so I'm not
sure if this has any importance where breeding is concerned.
I dose KNO3 (stump remover), Flourish, and Flourish K. None of it seems to
bother the eggs or fry. Unless, of course, that's what's getting them. I
don't think so.
I can confirm the fact that otos are egg depositors: the female's got an
ovipositor! It freaked me out when I first saw it poking out of her. She
eventually holstered it and soon after I found the first fry. That's when
it dawned on me what the protuberance was. It's emergence seems to be an
indicator when the time for spawning is nigh.
I was fortunate enough to witness the actual deed that led to the second
batch of fry. Basically, the male harasses the female who occasionally
gets spunky but stays aloof for the most part. As the event approaches,
the male wiggles up next to the female who is attached to the glass in the
usual oto way. Slowly he wiggles his way up above her and bends over her
in the "T" position. It takes a split second and then it's just like
nothing happened. I want to capture it with my video camera.
>I'm no otto expert, but I found your post really interesting
>and decided to take a quick work break and search google.
That's really nice of you, Shireen. Thanks!!! At least it got you out
from under the thumb of "The Man" for awhile ;).
> From http://www.thetropicaltank.co.uk/Fishindx/oto-affi.htm
> "Eggs are laid on the leaves of plants and hatch in about 3
> days. Provide plenty of algae, green food and tiny
> particulate foods, such as the liquid suspension types, for the
I think the otos will lay eggs on any hard surface, but I can't say for
sure. That's one activity I haven't witnessed. I haven't discovered the
eggs before they hatch either.
>I'm wondering if you could make a liquid food supplement
>for them, something rich in protein to help growth?
>(There may be some recipes at the live food
>list at http://www.actwin.com/fish/live-foods/ )
The more I think about it, the more I think they're starving and for a lack
of greenery and not a lack of bugs and stuff. I had considered liquefying
some tasty lettuce or other veg in the blender, but resisted the temptation
because I didn't want to upset the nutrient balance in the tank. That's
why I'm going to move them if and when I find some more.
I been entertaining the idea of putting a pane of glass or acrylic in one
of my fish only tanks that has the ability to produce prodigious amounts of
algae. Later, I'd just put the pane in the tank with the fry.
>Or make some green water?
I hadn't thought about green water. That's a great idea, but I actually
have trouble making green water. I tried to grow some for moina I was
culturing and never got a good growth going.
>Or buy a liquid food at your LFS. (I forget the company that
>makes it, but there's two types, one for livebearers and another
>for egg-layers. If you have difficulty finding some, let me know
>and I'll try to find some for you.)
Is the liquid food you're talking about called "Liquifry"? They've got it
around here, but thanks for the offer to find me some. I've also thought
about the stuff like Roti-rich.
>A few websites mention that breeding is similar to corydoras
>cats. There's a nice otto page that has a link to how to breed
>corys at http://userpages.umbc.edu/~rrhudy1/otto.htm#bred
I think at least one connection with Corydoras is due to the fact that the
addition of cooler, clean water seems to trigger the spawning behavior in
the otos. Each spawning in my tank took place within a day or so following
a water change. I'd usually discover the fry during the next change. The
water I use for changes is usually 20.6'C (69.0'F).
>Hope that's useful and please keep us updated. They are
>adorable little fellas, those ottos, and I'd love to try breeding
>them someday too.
That's *definitely* useful, thanks again. I will post anything that I
learn from future spawnings and I'll definitely post if I am able to
successfully get some past fryhood. Sorry the post is so long, but I get
carried away when it comes to this hobby. I also apologize for the slow
response...it's been a long day.
Knoxville, Tennessee USA
mailto:grendel at usit_net