Am I overstocked?

[TallPaul]

Fish that eat algae will only feed on certain species of algae. In the case of Otocinclus species, they will readily consume diatoms and common green algae, but not "problem" forms like green dot, brush, beard, hair, etc. Bristlenose plecos and Farlowella species, are much the same. They graze surfaces because all submersed surfaces develop a biofilm, and in addition to algae these biofilms contain various microorganisms on which most fish will feed, and which are especially good for fry.

If otos are introduced to an aquarium relatively free of common algae or diatoms, they usually starve. Dried leaves such as oak, beech, maple can be collected after they fall, dried, and placed in an aquarium. Otos will graze these incessantly, due to the biofilms and the infusoria that readily appears on dried leaves once submersed is the best food for fry of any species.

Having kept mine now for 2 months my experience with them is that they devoured diatoms and have had very little interest in much else besides biofilm. I had a small amount of algae on the glass, I assume it was green algae although it looked brown, and they were uninterested in it.

The algae on the glass is simply from too much light. Having altered the photoperiod and doing a bit more cleaning it is gone completely.

 

[Sarah73]

I had otos for a while. Mine LOVED zucchini. They ate green algae, algae wafers, fruits, even flakes sometimes. Really just depends.

 

[TallPaul]

Well, I'm slightly less overstocked. Worryingly I lost an Otocinclus today. It was just lay at the bottom of the tank all day behind some plants. I became worried and gently tapped him with my plant tweezers. They usually fly off when it comes anywhere near but this one didn't move.

I picked him up gently and let go and he just sunk back to the bottom. After fishing him out I did a water test, no ammonia, nitrites or nitrates to be concerned about.

Checked the pH and it appears to be 0.2 lower (more acidic) from 6.8 to 6.6, but that might just be my eyes under the kitchen lights.

The water is changed twice a week and it is between 30 and 50% change every time. This is way more than necessary as the heavy plant load ensures I never have ammonia problems in the tank. That's the one thing I am super vigilant of and most confident about.

Three different things have happened.

1. I introduced Ember Tetra to the tank
2. I treated algae on the bog wood with Easy Carbo (gluteraldehyde).
3. One of the Otos was rasping from the filter sponge.

I believe that number 3 is the cause. There are definitely marks on the sponge where an Oto has eaten from it. I assume that he has taken too much plastic in and ingested it causing poisoning.

 

[Byron]

I would be more concerned over the "Easy Carbo" being ingested, or rather the glutaraldehyde. This is poison to fish, and an oto grazing over wood treated with this could well suffer.

No problem with the pH.

The water is changed twice a week and it is between 30 and 50% change every time. This is way more than necessary as the heavy plant load ensures I never have ammonia problems in the tank. That's the one thing I am super vigilant of and most confident about.

Your water changes are fine, but your reasoning--if I read this correctly--is not. It is not anything we can test that is behind water changes, but all the things we cannot test but know are there. If you want to change your schedule, a single weekly water change of 60-70% of the tank will benefit more than two smaller changes.

 

[TallPaul]

I would be more concerned over the "Easy Carbo" being ingested, or rather the glutaraldehyde. This is poison to fish, and an oto grazing over wood treated with this could well suffer.

No problem with the pH.



Your water changes are fine, but your reasoning--if I read this correctly--is not. It is not anything we can test that is behind water changes, but all the things we cannot test but know are there. If you want to change your schedule, a single weekly water change of 60-70% of the tank will benefit more than two smaller changes.

You suspect the "glute". I stopped about 3 days ago but I think it may already have had an effect. Only one Oto went for the sponge though and all the others are seemingly fine. I was cautious over the Easy Carbo and under dosed but they could still have ingested too much after I had treated the bog wood.

The others are swimming freely, no tiredness or any other indicators.

As you say, I've stopped the glute and am vigilant for now to see what happens.

If after a week I may consider adding more Otos, as long as they are able to feed. I may also remove the sponge as all it does is kill the flow for the pump output.

 

[Byron]

You suspect the "glute". I stopped about 3 days ago but I think it may already have had an effect. Only one Oto went for the sponge though and all the others are seemingly fine. I was cautious over the Easy Carbo and under dosed but they could still have ingested too much after I had treated than big wood.

I'll observe on a couple of things from this. First, wood will readily absorb any liquid it comes in contact with, and it can take weeks and months for the substance to leach out. This is why wood treated with bleach should never be used in an aquarium' drying, boiling, etc will not deal with toxins absorbed.

Second on the glutaraldehyde. I know some will use products like Excel, API's CO2 Booster and Easy Carbo as a so-called liquid carbon supplement, and claim the fish have no issues. False. These products all are glutaraldehyde and water, and glutaraldehyde is a powerful disinfectant used in hospitals to disinfect surgical instruments, in embalming fluid, in anti-freeze, in ship ballasts to kill pathogens, etc. At recommend doses it will kill some plants; at higher levels it will kill all plants, bacteria and fish. The fact that it effectively kills algae should sound serious warning bells. Not every product allegedly "safe" for fish really is; even if the fish don't turn belly-up, they are still being affected as this and every substance in the water is taken into the fish's bloodstream via osmosis, and these do impact the fish.

The above is just observation as general guidance to anyone reading this.

 

[TallPaul]

It seems my tank may be suffering an outbreak of mass stupidity, I had to rescue an ember tetra from the rear compartment. It must have jumped the gap so I've had to drop the water level a bit more to avoid that from happening again.

It was incredibly difficult to get the fish out, the only way was to siphon it out. Poor thing had to go all the way through the siphon hose, into a bucket and then get released back into the tank.

 

[seangee]

I don't remember what your tank is but if it is a Flex the easiest way is to remove the lower vent cover. Empty the rear chambers of media and hardware and "chase" the fish back out through the vent. Still requires plenty of patience so prevention is definitely better than cure.

FWIW I have good sized colonies of shrimp and MTS living in the back of mine and I leave them to it. My Nerite comes and goes as he pleases.