Otocinclus gets stuck in sponge filter

[Lama]

I don’t have a photo of this, but have had two incidents of our Otocinclus going into the tube for the sponge filter and getting themselves wedged into the cap where the airline attaches.  After the second occurrence in two weeks, I decided to remove the green plastic tube from the top and am hoping this doesn’t happen anymore.  Might there be some other actions I can take to help prevent this problem?  We have a size large Aquarium Coop filter in a 20 gallon planted tank.  The Otocinclus seem to be ok so far; immediately after, I observed red scrapes on the fish around their head and gills.  But the redness has improved and it seems to be eating (full belly) and flitting around normally.

[jwcarlson]

The tube helps the lift (at least some).  I'm guessing you'll be just fine without the tube.  But if you wanted to put the tube back on you might be able to cut a little course foam to plug off the top of the tube so the Otos can't get down there.

 

Also consider that they're going in there because they might be hungry and cannot find food elsewhere.  Just a thought, not sure if there's any merit to it. 🙂

Edited February 23, 2022 by jwcarlson

[Lama]

jwcarlson, thanks for your input!  I wasn’t sure if it would affect airflow if I were to put foam in the tube and opted to try removing the tube.  I will keep it in mind as an option going forward.   As for food supply, I don’t think that they are struggling for food but, perhaps there is a certain flavor of algae they might be in search of?  I also wondered if they are interested in the current the airflow provides?  It’s a heavily planted tank with Java moss, sword plants, Anubias, and a couple varieties of stem plants.  There are also several natural rock caves to hide in/around.  I also toss algae wafers and Repashi solient green in when I see the previous feeding is consumed usually every other day).  Tank mates are 7 harlequin rasboras, 5 Corydora habrosus, and 5 baby cherry shrimp.  There are also some bladder snails.  7.6 pH, 0 ammonia, 0 nitrites, and 20 ppm nitrates.  GH 5.

[Flumpweesel]

Maybe make lid out of that plastic canvas it's holes should prevent the fish going in but let the bubbles out without restriction just cut a piece a little wider than the tube make a hole in the middle and slot it around the air line and slide it down to the top.

Hope that makes sense. Ask if you need me to explain better

[CT_]

I suspect blocking the uplift tube with mesh or foam would restrict the flow more than just not having an uplift tube, but the only way to know is to test it.  Another option if you really want the flow is to use the ACO power head.  There's pros and cons to that but it is an option.

[jwcarlson]

On 2/23/2022 at 2:49 PM, CT_ said:

I suspect blocking the uplift tube with mesh or foam would restrict the flow more than just not having an uplift tube, but the only way to know is to test it.  Another option if you really want the flow is to use the ACO power head.  There's pros and cons to that but it is an option.

There's an idea, if you've got an old power head you might be able to use the guard thing that pops off to fence the Otos out.

Any restriction of the tube is likely to cause some air backing up and then *glugging* out.  So the best bet might be what you already did.  They can't get down into the filter itself, though?  Through those openings?

[Lama]

Thanks for all the ideas!  I do not have a power head…just got into the hobby last year.  I do have it set up with an air stone to keep the bubbles on the smaller side; initially when I considered blocking off the tube in some way, I figured it would cause “glugging”.  So my first experiment was to remove the green tube and see if that would solve the problem.  The Otos can’t get down into the filter (inside the sponge), the widest part of their bodies get stuck in the cap (where the airline tubing and airstone connect).  My thought was with the green tube gone, once they discover they can’t fit, they will at least be able to work them selves out in multiple directions vs. having to back themselves up the green tube.  Hopefully it won’t be a problem anymore, but good to have something else I can try.  Maybe this is a stupid question, but what might be the consequence of not having enough lift?  Not enough surface agitation?  Poor circulation?  I’ve also seen (in an aquarium coop video) there is a way to attach/stack another sponge filter to the top of the bottom one.  Would this solve the lift issue…if I notice problems?

[CT_]

On 2/23/2022 at 1:50 PM, Lama said:

Maybe this is a stupid question, but what might be the consequence of not having enough lift?  Not enough surface agitation?  Poor circulation?  I’ve also seen (in an aquarium coop video) there is a way to attach/stack another sponge filter to the top of the bottom one.  Would this solve the lift issue…if I notice problems?

not a stupid question.  The unhindered movement of the bubbles is really important in creating flow through the sponge.  You don't need crazy flow generally.  just enough to keep the water circulated and to move enough across the filter so that the bacteria can get to the ammonia and nitrite.  you'll get less mechanical filtration from the sponge with less flow though so your water may be a "dirtier" looking.  but that's subjective and up to you; it won't harm the fish.