To each his own I suppose... it's good to hear a different opinion, can certainly respect that. Have cycled many tanks both ways... and yes, I know the shrimp is already dead, but it too was once alive very much like the hearty Damsel. Cycling can be done either way, do it how you prefer, one is not mutually better than the other when done correctly and closely monitoring the water chemistry especially the ammonia level. Or just get some sand or live rock from an established tank. Ive noticed that:
1. It costs 4 dollars more to cycle a tank with a Damsel as opposed to a peice of shrimp. Hardly worthy of cost analysis. Damsels are very cheap, 5 bucks each at our LFS, cycling with a live fish also teaches one to be more vigilant and encourages better awareness.
2. Damsels are easily bred in captivity, so I cant see how it really encourages the LFS to sell more of them for cycling. They dont make anymore profit from the sale of a Damsel then a nice goldfish, which is easier to maintain. Besides there are so many varieties, most people I know like to purchase them for their colors, not just for cycling...
3. Ive done it both ways and have never lost one. Have tried to keep a vigilant eye on the tank during cycling paying close attention to dissolved ammonia levels and a would definitely know if its one inhabitant was missing.
4. The aggressive nature of this fish depends on the species, Humbugs, Three spots and Cloudies can be aggressive towards members of the same species, thats why you only keep one. The Green and Blue Chromis are relatively peaceful, I have six Greens peacefully housed together in a 125 gallon tank. Its difficult to generalize with accuracy that all damsels are mean and aggresive when there are over 17 know species in the same family. Territorial aggression is largely dependant on the species and size of the inhabitants its housed with, any fish can be aggressive if the conditions are right, i.e food, territory, overcrowing, lack of refuge areas... guess Ive just been lucky, and have been able to manage these little fish without too much difficulty. Then again part of the reason many enjoy this hobby is because of the challenges marine species present... Just because something is "the norm" dosent mean its better. Anyone can cycle with a piece of meat. It takes a skilled aquariust to keep something alive.
Best regards
Phixer