THROW A GOLD FISH IN THERE FOR ABOUT A MONTH, THEN AFTER YOUR LEVELS ARE STRAIGHT... PUT IN YOUR DEVIL HE WILL BE STRAIGHT FOR ABOUT A YEAR BUT THATS PUSHING IT
ya i hope ur gonna get a WAY larger setup pretty soon for that red devil. it takes like at least 3 weeks to cycle a tank that will fit a red devil. u can speed that up in various ways though. the 10 gallon will only work for a few weeks if that IMO
and no glowlight tetras do not glow under blacklight
dont buy a fish that will easily overgrow your tank in about 5 seconds..... unless you know for sure you can upgrade as soon as needed
a community of tetras and maybe some surface feeders like hatchetfish would look great in a 10 gall. heavily plant it and you have a beautiful low maintenance tank (assuming you dont heavily stock it) plants in smaller tank can really reduce the need for water changes (as they soak up nitrates )