Yep i only found out about it a while back when i used to have a fancy long tailed german blue diamond guppy. I moved him to a strongly filtered 30gal tank which was heavily planted which i thought would be heaven for him and i bought him a heap of females. At first he was resonably active and swam with all the other guppys but over the next week a tear appeared in his tail, so i added a bit of melafix to the tank to help it heal just thinking he was still sorting out a pecking order with the resident male despite them having 6females between them.
The fin healed very quickly and was totally healed within a week, but only days later a new tear appeared. This continued to happen over and over again and his activity levels started to drop and he started spending more and more time on his own at the bottom of the tank away from the rest of the guppys in planted areas and the females took no interest in him what so ever.
It drove me crazy as to what was going as the resident male guppy paid him no attention at all and the guppy himself never appeared to have any tail eating deseases- eventually he died, and a couple of weeks later i started researching into the posibilitys that the filter current could have had somthing to do with his tail splitting and death and, well thats when i found out about long tailed guppys and big tanks/too strongly powered filters.