Somethings killing my guppies; HELP?

Question

I have a 50 gallon community tank with guppies; 2 platies; 3mollies; 4 Danios; 3 Neon tetras; and 3 cory cats. Guppies out numbered the rest of the fish by quite a few. Recently; however; my guppies number have dwindled dramatically I currently only have 1 adult and about 5 guppy fry (big enough not to be eaten whole) and a few little babies; the small ones are doing fine. Every couple days for the last week I've been finding dead medium to full size guppies with their tail completely missing. I originally thought it was my filter so I covered it so not fish would be injured; however; it keeps happening. How do I find out which fish are causing the damage? Do you think it's just one? And why is this happening? TY for your help

I have been keeping a close eyes to see if I can find the one thats doing the damage; but it feels like every thing's fine and I turn around and I find a dead fish with its tail removed down to the base but no further; or see a guppy part of its tail fin missing. It's def. not fin rot since its only affecting the guppies.

Answer 1

mollies have been known to tail nip ,unless you watch them i dont think you can say 100 percent which fish is doing it.
is it not possible you have a disease in your tank possibly fin rot and that affects the tails to,check out each of your fish and see if they have any tail parts missing,

Answer 2

this is pretty simple....actually all the other tankmates could be at fault. its pretty hard to just number them off.
i assume the guppies you have are fancy. fancy guppies have really beautiful tails that not only attract buyers and breeders, but also other tankmates. (i've did a gupppy report so i kno a fair amount about this subject)
their tails would attract their tankmates and so they would end up chasing them around and nipping / biting their tails off. its really common amoung fancy guppies. i think tho that mollies nad platies are mainly the ones biting the tails off being a regular choice for being with guppies. frys are not affected until they get older b/c their tails are either too small or haven't shown their color.
because of these beautiful tails, other tankmates would chase them leaving you with a *gasp* tailess guppy.
anyways, being tailess isn't the only thing that is probably killing them. some would die w/o a tail but others are probably prone to infection. this infection includes fin rot. i actually had a guppy with half her tail nipped off. i put her in a hospital tank and some medication (its that blue dye thing...) and her tail grew back on. i'm not sure if it'll work with the entire tail ripped off,.
so what's the best way to ensure this wouldn't happen again? its bascailly this: have only guppies. even though its only one type of fish, your aqurium would still look really pretty. (esp w/ those tails :D ) yea, i kno its harsh....esp. since guppies are known to be community fish, but its the problem with fancy tails.
a book i'll recommand (its the only that i copied off of in my report) is Guppies Today: a complete and up-to-date guiede by Spender Glass. there are full colored pages as well as talking about problems such as this in more detail. (i have horrible memory :P)

Answer 3

It's quite possible the danios are the bad guys here. Look at your remain guppies to see if any have badly damaged fins. Danios are known fin nippers and may well be killing the guppies one at the time.

MM