Fish Tank	1	2	3	4	5
Species	Oscar	Ram	Convict	Tropheus	Angelfish
Gravel Color	Brown	Black	Speckled	Sand	White
Food	Goldfish	Flakes	Brine shrimp	Pellets	Microworms
Plant	Pennywort	Lace plant	Plastic	Algae	Swordplant
Size	50 gallon	20 gallon	30 gallon	75 gallon	40 gallon

So, the answer is: the Tropheus lives in the 75 gallon tank!