It's one of those Tetra heaters that are pre-set to 78 degrees.
I had about one a while back that was like 2-7 gallons I believe, but it didn't heat the water above 73 in the 5 gallon. I moved it to Claude's 2.5 gal tank when I bought him, it keeps the water between 75-78 degrees.
For this boy I bought one of those Hydor minis, but I didn't realize it only changed the room tempurature slightly. I went to exchange it and got this one instead. This Tetra heater is 50 watts and it can be used for up to 10 gallons, so I was hoping to have more success. I would buy him a nicer adjustable heater, but I have no money atm and these two were the cheapest.
I just snapped a few pictures of him though! I'll post it in the picture section after they're done uploading.