I would say otos need a regular food source. If you notice that your tank is clean of algae (which it will be very quickly as they're quite efficient), I'd pretty much always have some veggies for them to munch on (don't forget to remove older veggie that's been in the tank for, say, 24h). It's important to vary their diet somewhat, so here's some options for them:
- flesh veggies like cucumber and zucchini (don't forget to remove the seeds off the zucchini as they won't eat them and they'll end up everywhere in the tank, causing a huuuge mess)
- spinach (just tried for the first time yesterday and the otos seem to love it)
- peas (never tried on my otos yet, but I hear it works from a recent post on the subject). Good news is that the
betta can eat the peas too. Do be very conservative with the portions, though. I'm talking one pea max, with the flesh mashed in little pieces, and the skin removed (and in the bin, not hte tank). I'd drop the pea in a bowl at the bottom of your tank so that if they don't find it, it's not a mess. Also, they're pretty smart and will end up always checking the bowl for food after a while.
- I sometimes push protein pellets in fleshy vegetables, as otos need some amount of protein once in a while, although not much
- They love algae sheets. You can get them from your fish store (at least we can). They're exactly like the nori that you'd eat with sushi, except that they're fish food.
That sort of variety should make sure your otos are nice and healthy.
Another piece of advice: You can use veggie clips for bigger flesh vegetables (I swear by them since I've started using them). I'd definitely cut generous slices of the flesh vegetables to increase the chance of them finding it. Oh, and of course don't forget to thoroughly rinse them before you put them in the tank. You never know with pesticides and stuff.
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