| Rachov's Nothobranch Nothobranchius rachovii |  |
| Rainbow gudgeon, Peacock goby Tateurndina ocellicauda |  |
| Ram, Butterfly cichlid Papiliochromis ramirezi |  |
| Red Humped Eartheater Geophagus Steindachneri |  |
| Red finned loach Botia modesta |  |
| Red finned silver dollar, Moon redhook Myleus rubripinnis |  |
| Red tiger scat, Green scat, Spotted scat Scatophagus argus |  |
| Red zebra Metriaclima estherae |  |
| Red-eyed tetra, Niger tetra, Arnolds red-eyed characin Arnoldichthys spilopterus | |
| Red-fin shark Epalzeorhynchos frenatum |  |
| Red-finned ram Papiliochromis altispinosus |  |
| Red-line Rasbora Rasbora pauciperforata | |
| Red-tailed puffer, Red-eyed pufferfish Carinotetraodon irrubesco |  |
| Redheaded cichlid Vieja synspila | |
| Rice fish Oryzias latipes | |
| Rocket panchax Epiplatys annulatus | |
| Royal Panaque L027 Panaque nigrolineatus |  |
| Rummy-nosed tetra Hemigrammus bleheri |  |
| Rasbora maculata Dwarf Rasbora, Spotted Rasbora | |
| Rasbora pauciperforata Red-line Rasbora | |
| Rasbora vaterifloris | |
| Rhinogobius duospilus | |
Too many fish? Overstocked tanks stress the fish in many ways: competition for food and space, bullying from other fish, deterioration of water quality and increased concentration of disease vectors. A lightly stocked tank will always be easier to care for, with more stable water quality