I tried to match your photo to one of the species and then did a search. Here is what I found and hopefully I matched the fish correctly.
Family: Loricariidae (Armored catfishes) , subfamily: Hypoptopomatinae
Order: Siluriformes (catfish)
Class: Actinopterygii (ray-finned fishes)
Max. size: 7.0 cm SL (male/unsexed; Ref. 36885)
Environment: demersal; freshwater
Resilience: High, minimum population doubling time less than 15 months (Preliminary K
Gazetteer South America: Amazon River basin.
Red List Status: Not in IUCN Red List (NL) (Ref. 53964)