Smallest freshwater fish specie?

corydora sterbai aka dwarf cory

how about a bristlenose pleco? my biggest one is under 4in
 
Bumblebee gobies are not good candidates for this tank unless it becomes a truly brackish one. The bumblebee gobies are brackish, and while one species can survive in freshwater, they don't live nearly as long as those kept in brackish conditions.
 
Bumblebee gobies are not good candidates for this tank unless it becomes a truly brackish one. The bumblebee gobies are brackish, and while one species can survive in freshwater, they don't live nearly as long as those kept in brackish conditions.

That is a tricky one. The ones more commonly found in LFS's do great in freshwater, even long-term. There are some freshwater only varieties also. Online, just about anything is available so it is quite possible to come across the brackish-only varieties (although even those are arguably fine in freshwater). The whole status of the Bumblebee Goby is still in a bit of debate.


But they aren't really a good fish around tiny fish. They are okay with things roughly their size, but they do have a surprisingly big appetite. I've seen them down livebrearer fry to the point where you'd never think there were ever breeding fish in the tank. They are a pretty neat fish to keep them. Its how sneaky and slow they do are that makes it so interesting. They don't chase down their prey, they follow very slowly until it stops bothering to run away.
 
And just cause he doesn't toot his own horn, www.bobstropicalplants.com (Mgamer200o0) also has several great nano sized fish. I bought my sezond batch of celestial pearls from him.

Honestly, the vendors on this site are some of the best for nano type freshwater and I wouldn't look anywhere else if I was looking for some. Most LFS don't want to stock them. Usually when I have seen CPDs at a local shop here, they have been in the 7 buck range and owners know most people aren't interested in 7 dollar 1 inch fish. They just don't move.

Same for some of the harder to come across rasaboras.

However, i will add this. There are some big box "Pet X" stores out there that will get things for you. I know of one here locally whose general manager is also the fish dept manager and whose father has a fish farm/import business in Florida. He will special order thngs, especially if he thinks they will sell and/or he has someone that will take 2/3-3/4 of his initial order off the start. You might check around your area and see if you have one of these managerial gems. They are usually the ones with the clean, healthy looking tanks.
 
Ha, read the title real quick and I thought it said, "smartest freshwater species". That would be hard to figure out.
 
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