My Oto's Bizarre Behaviour

I haven't had my otocinclus very long, but always thought they were strictly algae eaters and if you were extremely lucky you might be able to get them to eat some veggies or algae wafers. After tonight, I no longer believe that. At least not for one of my otos.

I have never fed frozen beef heart before since I rarely feed frozen, but my niece gave me some to see if my fish would eat it. It quickly sank to the bottom and none of my fish are big bottomfeeders except my BN. After about an hour, I decided to do a substrate vac because the beef heart had fallen in the area where my Rainbow Cichlids were breeding and they and the BN were fighting because he kept going into their territory to eat it. When I went to vacuum it up, I almost sucked up an oto because it was voraciously eating a piece and wouldn't let go or move! On top of that, this was the first time I had ever seen one of the otos on the substrate. I left a few small pieces and when I went back to try to get a pic he tried to carry it up off the substrate. After poking around, I found a few others that said theirs had eaten blood worms. Have any of you experienced anything like this?!?

*I don't plan to encourage this diet as I don't think it's good for them, I'm just curious.*

The first pic is the little pig and the second is the chunk of beef heart he was trying to take with him, lol.

 

I have seen them on the substrate plenty of times, and wondered if they ever clean up uneaten food, though I haven’t actually seen this happen for sure. I have never given them beef heart or bloodworms. I have read that feeding them with brine shrimps helps to condition them for breeding, but mine don’t seem to take any notice of brine shrimps.

 

I haven't noticed mine eating any meaty foods but that's not surprising since my other fish don't give them much of a chance. They have learnt to graze on these tablets though. They are quite long lasting even with other fish pecking at them:

https://www.sera.de/en/product/freshwater-aquarium/sera-spirulina-tabs-nature/

 

They are known omnivores, but think you'd be careful with beefheart. Most omnivores have difficulty to digest proteins / fats in it.

 

I read a very interesting discussion on these which referenced some of the study and research available. Their herbivore status seems to come from a study sighting the shape of their intestines and stomach. However, it has also been observed that other fish with similar intestinal shape do consume invertebrates and moribund fish flesh.

They go through harsh conditions in their natural habitat. Dry season can leave them cut off from rivers and in shallow puddles and ponds. Given their large numbers in the wild, in harsh natural conditions and stress from human activity, it is likely that they are adaptable in what they eat.

I certainly have observed this in my tank. Their co-mimicking behaviour with pygmeus corydora extends to eating frozen food from the substrate with them.