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Otocinclus catfish


  1. Aquatic Plants Digest V1 #257
    by (WRIGHT HUNTLEY ) (Mon, 21 Aug 1995)
  2. otocinclus fry
    by (Mon, 21 Aug 95)
  3. Breeding otocinclus!
    by "David Ozenne" <dozenne/> (Thu, 11 Jan 2001)

Aquatic Plants Digest V1 #257

Date: Mon, 21 Aug 1995

 Cathy Drzyzgula <> wrote
>   Through no plan of mine my otto cats spawned on Friday and now the
>fry are free-swimming (free-clinging?). 

> Any ways to change the water and make sure
>no fry get sucked up, or do I just check after siphoning and do it
>gently?  I've never raised any fry before so any suggestions greatly
First, congratulations. I'm green with envy!

I would be inclined to start some infusoria in the 10G tank. The 
already added plants plus a couple of drops of LiquiFry for egg layers 
should do that nicely. I don't think *any* cats are 100% vegetarians.

Add some snails once the fry are free swimming (I've seen ramshorns eat 
eggs), for the overfeeding you need can be turned into snail poop, 
which is good infusoria fodder.

Water changes are easy. Just put a net over the underwater end of your 
siphon hose. If you don't have good biological filtration, you will 
need to change small amounts frequently to keep ammonia, nitrites, and 
nitrates down.

I keep a couple of fishbowls out on the patio to make green water for 
those fry that like veggies. I bet the otos would dig a squirt of green 
juice, once in a while.

Good luck,


otocinclus fry

Date: Mon, 21 Aug 95

> From: Cathy Drzyzgula <>
>    Through no plan of mine my otto cats spawned on Friday and now the
> fry are free-swimming (free-clinging?).  I moved the eggs to a newe 10
> gal tank (rainbows in original tank) and have added a few plants
> collected from various tanks.  I smushed 1/2 and algae wafer on the
> (bare) bottom of the tank too.  Any suggestions for me?  How often do
> I change water in the tank?  All I've read about fry says to feed
> small amounts several times a day, but since the adults seem to feed
> continuously I thought a small steady amount of food available made
> more sense--do you agree? Any ways to change the water and make sure
> no fry get sucked up, or do I just check after siphoning and do it
> gently?  I've never raised any fry before so any suggestions greatly
> appreciated.

I've not raised this type of fry before but let me share some experiences
with Betta and Gourami fry. A danger of keeping fry in a small tank
and trying to feed large amounts of food is that the water can go
poisonous quite quickly. For carniverous fish with large fry like
Bettas and Gouramis, I started feeding live brine shrimp almost
immediately. I NEVER used the terrible egg paste formula sold in pet
shops. Otos are not carniverous so you want lots of soft green algaes.
I think the live algaes are much preferable to dead ones in tablets or
flakes so why not put your tank where it can get bright light esp
sunlight (but not overheat). I feel that fry always do lots better with
lots of floating plants such as water sprite or salvinia. With green
algae, there is usually lots of infusoria too (but your baby cats will
eat the soft green algae I think)

When changing the water, I used airline tubing as a siphon. It's slow
but you can avoid sucking up fry this way. I always added water out
of one of my other tanks. Since I was feeding nauplii several times a
day, I changed water daily or every second day. This would not be necessary
in an algae/plant only tank. You could do it weekly just to replenish

How did you induce the otos to breed? What did they choose to put their
eggs in? I have a large tank with only otos, 1 farly, 2 corys and many
baby platys. Do you think I could induce the otos to breed? That would
be great!

 - Steve

Breeding otocinclus!

by "David Ozenne" <dozenne/>
Date: Thu, 11 Jan 2001

Back in October, Bob Dixon asked about breeding otocinclus.

I've had otos in my tank for years, and occasionally saw a 
egg-laden female, but never any evidence of eggs/fry.  (I
have plenty of things that will eat fry, so no surprise
there.)  But when I moved last June, I'm pretty sure I was
down to only two otos in the tank.

The other day, I spotted three otos at once.  Odd, but I
chalked it up to faulty memory.  But then, the next day,
I saw four.  Now, there might have been three all along,
but no way were there four.  So my success in breeding 
otocinclus now matches my success with black neons!  (I
had one of those survive to adulthood a few years back.)

Truly amazing when you consider that there have been at least
50 zebra danios in that 70-gallon tank, in addition to 
loaches, tetras, barbs, SAEs, and a white cloud or two, for
most of that time.  I figure the only possiblity is that
they were hiding and growing in a giant tangled mass of
java fern 'windelov'.  Another good reason to keep a well-
planted but not-so-well-pruned tank!

David Ozenne
Fremont, CA

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