Hardy Fish (otos)?

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Aquarium Advice Activist
Apr 20, 2022
Near Reno, NV, USA
I am suggesting for my school to get a fish tank. I was thinking a 20 gallon (75 Liters) with 10-15 neon tetras.

I was also thinking otos but after some research, I found there were many mixed opinions on how many otos in a 20 and how easy they are to take care of.

Are otos a good easy beginner fish? I was really looking for something pretty hardy and fun to watch. Any other suggestions? Thanks!
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I added otos into an already cycled tank which i had left the lights on for 12 hours a day for 3 weeks while the tank cycled and had a good amount of algae/ biofilm established for them to eat before they went in. They completely cleared the tank of brown algae in about a day, left anything green and they then i fed them algae wafer and vegetables, and they do eat a little leftover food.

But, i would hardly call them fun to watch. If i see them during the day they just sit there on the wood or under a leaf, I only see them moving about after lights out or during water changes moving away from the syphon.
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Ok, so maybe otos maybe not, ill have to think about that a bit. I was also thinking maybe Mystery snails. I find them fun to watch, you can leave the room for 5 minutes and when you come back, you don't know where they've gone. I do know however they produce a lot of waste and if I keep more than 1, they might reproduce. So, does anyone have any good cleanup crew recommendations? I think the substrate will just be plain ol aquarium gravel. Thanks for any input!
Orange Dwarf Mexican Crayfish - Cambarellus patzcuarensis is a fun scavenger.

Not over feeding to begin with is a good thing.

Check out the getting Started article in my signature link below, it can give you some great basics and key information for healthy and happy fish keeping.

I think one Mystery snail, they usually clean up super well, and start out smaller when you buy them, and maybe a Nerite after the tank stabilizes and or gets some algae/ biofilm for it to eat.

Check out if any of your lfs have Green Neons, they are pretty and sometimes the Neon Tetras are a little weak. Worth at least checking them out.

Have you considered some Dwarf Corys? You can have a nice bunch of them like 8 and they are so small they are more like 3 bigger ones.

There are other smallish cories you might consider as well.
Can you get a bigger tank (more than 20 gallons)?
At least go for a 20 gallon long so there is more surface area.

Otocinclus catfish are not beginners fish and are not suitable for a new tank that is less than 6 months old. They feed mainly on algae and biolfilm (the slime on rocks, glass and ornaments). If there isn't enough, they starve to death.

Most Otocinclus are starving when they are at the shop. They don't get fed well, or at all when in the exporters in Asia or importers. If you get Otocinclus, look at their stomachs. The fish should have round bellies that stick out a little bit and they should not have sunken in bellies. Fish with sunken bellies usually die within a week or two.


Freshwater crayfish are not suitable for fish tanks. The crays are nocturnal scavengers and will eat plants as well as catch and eat small fish during the night.

Shrimp (glass or various coloured shrimp) and mystery snails make for a better clean up crew. However, they and the fish should not be in a tank that is cycling (developing the beneficial filter bacteria) because ammonia, nitrite and high levels of nitrate (above 20ppm) will quickly kill invertebrates like shrimp and snails.
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