Otocinclus cocama spawning

[unissuh]

Posted this on a couple of other boards, but thought I’d stick it here as well.

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Don’t see much about Otocinclus breeding around at all considering how common a fish they are. Does anyone know if this species has been successfully bred and reared before?

[Colin]

Excellent – good to see how it is done

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[Matt]

Brilliant.

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[unissuh]

QUOTE (Colin)

How are you getting on with fry?

On day 10 from hatch now so I think the hardest part is almost over. I think I only got 10 eggs from the first spawn & I’ve seen at least 7 which is about as many as I expect to see out. Second spawn didn’t go too well, that happened a few days ago but most of the eggs vanished around on the day they were supposed to hatch. Not sure what went wrong since it’s a species tank.

I’ve done O. vittatus or vestitus a few times before (not sure which one they are) which helped.

QUOTE (Matt)

Never seen any spawning report for this species before.

What are your water parameters if you don’t mind sharing?

Copied and pasted from a post I made elsewhere:

QUOTE

I did not perform a water change out of routine (typically 50% on the weekend) prior to the spawn, however there was a period of 5 days (starting 3 days before) with very low atmospheric pressure and stormy weather which I suspect acted as the initial trigger for spawning. I only realized the first spawn had taken place when I observed newly hatched fry flopping around on the substrate. At this point water parameters were 25-26°C, pH 6.6, 2 dGH, <1 dKH, 1 ppm PO4 and 10 ppm NO3 and I had no reason to think that they were any different when the spawn was estimated to take place.

[Matt]

Cheers for the info, and please keep us updated on progress with the fry.

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[ste12000]

Nice thread, its rare to see any spawnings of Otocinclus so i enjoyed this thread immensely.. Keep us updated!!

[unissuh]

Cheers guys, going pretty good so far (I think).

Just hatched:

Day 3, 6 mm:

Day 4, side:

Day 5 (eating well):

Day 12, 8 mm:

Day 12, side:

I saw 8 of the 10 yesterday, so it looks like it’s going OK. Maybe 3 fry from second spawn, not sure yet.

[Matt]

Great photos! Do the fry just feed on biofilm or are you offering them something specific?

[unissuh]

I’d probably have gotten away with not supplementing diet with so few fry but didn’t want to risk it.

Used an old trick to start out with – make a sludge with powdered fry food (I’ve been using Sera Micron) and squirt a little in the areas that the fry sit with a transfer pipette. Have also been trying something new that I think works better, just get a algae wafer/pellet and rub it over the surface the fry are feeding on. I think the important part is to coat the surface that the fry are grazing on with little food particles they can find. Not sure which method works better yet, but at least with the latter the adults come over and hoover up the bits that don’t stick. You can tell where the fry will go because they home towards areas of high flow, mine all come to the front glass where the filter output is pointed.

They stop homing at about 6-7 days and go wandering all around the tank. They start being attracted to adult food around now too, so it’s no big deal. I tend to feed nori sheets mostly, with a few algae wafers in between. I think they only come out to eat when they can’t find enough biofilm, so to answer your question, it’s probably mostly biofilm they’re eating, but I am also offering lots of food.

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[Matt]

Cheers for the detailed info.

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[unissuh]

Yep, have been keeping them together for now. Goes OK as long as adults don’t get too pushy (unlikely). Not entirely satisfied with this method though, if/when I get more spawns, might try things like fry savers to concentrate fry.

[unissuh]

Few more pics to bring this up to date-ish:

Day 21, 10 mm:

Day ~28:

Day ~28, 12 mm:

Unfortunately I didn’t get much further than this – they just started dropping off slowly until they were all gone. Saw the same thing with vestitus except they were just going into hiding, these definitely didn’t survive. No idea what it was, could’ve been something in the tank, wrong diet…anything really.

Back to square 1.

[Matt]

Thanks for the update Garrett – what a shame you lost them. Presumably there are plenty of algae, diatoms, etc. in the tank for them to have reached 10 mm?

[unissuh]

Yep, and I’m wondering if that was actually part of the problem.

My reasoning is diatoms, biofilm etc is great for maintaining adult Otocinclus, but whether the little ones need a different (i.e. richer) diet to grow is a different question. I haven’t had this issue before with vestitus but I vaguely recall these actually came out of hiding every so often to nibble on wafer/nori that I’d put in. The cocama fry didn’t touch anything else once they were on diatoms/biofilm. Once they were that size, I stopped coating all the walls with rubbings from the wafer too.

Next time I will try confining the young to a breeder net or box to make them eat what I feed – hopefully that will give me better results than letting them wander.

[Matt]

By “richer” diet do you mean higher in protein?

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