hmmm i buy becasue I want more /different /incompatable with current fish...
however, when my son first entered the hobby, he started with a 5g eclipse, people got him fish for his birthday...
10 neons, 2 cories, 2 bumblebe gobies, 1 betta, 5 glowlights an dtwo kuhli loaches...
all for his 5 gallon.
lol
I thought telling the family,"well I got him a fish tank so you could get him stuff for that." would encourage them to get him decor or a gift certificate for fish/stuff, but the LFS told them the bumblebee's and neons would get along great and they were "so cute".
so he got a five gallon and a ten gallon and surrendered a couple fish to my ten gallon ADF tank and my 55 gallon goldfish tank. Unfortunatly the gobies didn't make it(I didn't know their water requirements or even what they were at the time). but most everyone else did(although the neons succumed to neon disease eventually). I still have one of the cories. This was alittle over 5 years ago.
I'm sure that falls under one (or more)of the above mentioned catagories, but it all started because the LFS told my sister and mom that all these fish would be great together in a brand new 5 gallon aquarium.