Small Oddballs(Rare Fish Aswell)? -Inverts Too?

I was wondering if anyone knew of some smaller oddball and rare fish for an 81 cm Long 50 cm high and 36 cm wide (it's the Juwel Rio 125) and whether you know of any rares or oddball for this size tank please let me know!Also I already know of a few such as African Butterflys and Spiny eel.Any strictness on these fish/Inverts would be really helpful! Thank in advance!
Answers:    That is nearly a 35 gallon tank or 145liters.

Is this going to be a tropical tank? If so, I would recommend that you look into getting some loaches. For that size tank, in that are several loaches I would recommend.

If you have a tank with a hastily moving current I would suggest:
Dwarf Chain Loaches
http://www.loaches.com/species-index/yas...
Zebra loach
http://www.loaches.com/species-index/bot...

If you have a slow moving water flow surrounded by the tank, I would suggest:
Black Kuhli Loaches
http://www.loaches.com/species-index/pan...
Striped Kuhli Loaches
http://www.loaches.com/species-index/pan...

I have Zebra loaches and Black kuhli loaches. They are both a great totting up to any tropical tank.

A note about any of these fish, they are community fish that form nice little social groups. Don't grasp them in groups of any less then three, preferably 5 or more.

Another Note: Please trade name sure your tank is stable beforehand you put these fish in it. (that means running it for a month with other fish surrounded by it.

WARNING: Loaches are highly addictive fish to own. You may succum to Loachaholism. I originally bought a Zebra and another loach called a Yoyo loach to eat snails within my tank. It quickly became an thing.
Bubble bee gobies are adorable. they need brackish water though.

how about dignified fin knife gobies?
White fleas within my 10 gallon reservoir, drinking adjectives my fish?   Community aquarium "how" query?   Is it conventional for a womanly betta to back put her eggs surrounded by the Bubble nest?   Layer of nouns bubbles over sea contained by 29 gallon fish container?