Maybe fin rot?
it's not the shrimp, too small and are always on the bottom. could it be the SAE?Fin rot and most other diseases are a result of stress due to unfavorable environmental conditions. What exactly, who knows...
Another possibility could be the "ghost shrimp". I never had any that seemed overly aggressive, but there are some out there that grow bigger claws and might attack fishies.
pH: 7.8Another vote for fin rot. I had some long fin rosy barbs that had chunks of tail missing after living peacefully with tiger barbs for a couple months. It really looked to me like chunks were being bitten off, so I assumed the tigers had turned killer. A couple days after the last of the rosy's died, my tigers started getting ick. Turned out my nitrates were way high.
Check your tank for any other "pests" that might be introduced via the plants you have.(they may hide during the daytime if your have a lot of plants) I once had a small wood shrimp that I had not purchased take a ride into one of my tanks via a bunch plant I bought. He began pinching at the tails just like your noticing. (even though it looked really timid).
It probably is just fin rot though, if you have a good Disease ID book on hand take a look at the picture of what fin rot looks like compared to "nipped" fins, and see if your fishes tails have the appearance of one of them.
Where did you get goldfish from? I did not see any mention of it in his post.how big is this tank?
Goldfish have been known to nip.
Heck, they'll try to eat the guppy if they're the right size.
ps.. you got a cold water fish with tropicals. Not sure if that's so good.
i may take em out and see if it helps.My vote is for the ghost shrimp. Even though they are small, they do attack other fish. Being an invert, they are most active at night. Fish like to go all mellow usually and sorta pick a spot to rest, and ghost shrimp very well known to catch and attack fish.
goldfish? huh? there's no goldfishhow big is this tank?
Goldfish have been known to nip.
Heck, they'll try to eat the guppy if they're the right size.
ps.. you got a cold water fish with tropicals. Not sure if that's so good.
i just added 4 more neons so there are now 7I'm going to go out on a limb and go off in a new direction. Has anyone considered the fact that there is only 1 Cardinal in that tank and only 3 Neons in the tank?!? Characins need larger groups, even the peaceful little neon or cardinal can be a nippy fish if not kept properly. Groups of anything less than 6-7 of these fish are needed for them to be comfortable. These fish will nip at others and each other if not kept in proper numbers. Seems somewhat surprising until you consider another species of fish in that family: Piranhas! The nature is still there, it runs through the entire family.