They are "Golden Dojo Loaches", or, also known as "Weather Loaches". They are called Weather Loaches because they become much more active when the weather is about to change. They used to carry them on Navy Ships.
I think they are very fun fish, when they are doing laps in the tank they look like golden spiralling ribbons.
But I digress.
When we had just the 29 gallon tank I bought 3 of these loaches for it. They like their own company, and need a friend. The silly things kept disappearing, though, going over the back wall, and down through a hole underneath the filter system built into the tank. All three of them disappeared, and I stopped getting any, having learned my lesson.
Well, then the advent of my 75 gallon glass tank at an unbelievable price came about. We got the big new tank all set up, water parameters happy, got it landscaped. Then moved all the fish over, and unplugged the biocube, until I had time to clean it out and prepare it to become our Salt Water tank.
Fast forward, about 3 weeks. MM took the biocube outside, the tank that had been unplugged for 3 weeks, no light. No air. Just a little water at the bottom....
He dumps out said water, and I hear him hollering from the front yard
"Fish! I've got a Fish! Open the door! Fish!"
I go out the screen door and MM runs past me, hands cupped, throws open the top of the new tank, and practically throws this fish he's found into the tank.
He'd survived the entire time under the filter system. And for the last 3 weeks, with nothing to eat, no lights. NOTHING. Hence his name, Rambo Loach.
He also survived the 5 days of no power.
I really shouldn't be surprised. RamLoach might outlive us all....