[urbanrat84]

Hi amutti - Thanks for the reply. I notice you also have seahorses - what tank mates do you have with them in you 29g? In answer to your question, my tank is 48 gallon.

"They eat relatively large meat . . . I'd guess the wouldn't mind eating an expensive seahorse snack."

What is the LFS feeding them and how 'large' are the pieces you've seen them eat? Everything I have read on the nature of engineer gobies has said they are peaceful towards other fish bar small fish such as clown gobies. The sp. of seahorse I have are H. taeniopterus which are quite large - from everything I have read I find it unlikely they would view them as food, fry perhaps yes, but I can't say that from experience which is why I am here asking questions! Can you tell me your reasons for thinking they would eat seahorses?

rssjsb - I have CB Banded Pipefish (Doryrhamphus dactyliophorus) from Seahorse Sanctuary in Perth, Australia. While I have found Wet web media very helpful on a lot of marine topics and great as a general guide, there are things that I come across which is not consistent with information from other sources - seems that way in all things marine! My reading and advice I have received from ppl who have kept engineers long term is that once they form a pair, they harass any other convicts residing in the tank to death - regardless of the size tank they are in. I think the concept of keeping them in groups comes from the fact that they school together for safety when juveniles, there will be aggression towards each other as adults unless they are a pair. As for tank size, Wittenrich, Matthew L., "The Complete Illustrated Breeder's Guide to Marine Aquarium Fishes", p 242. says:
"A single pair can be maintained in a 20-gallon aquarium. A group of adults will require at least a 40-gallon aquarium. Once compatible pairs have formed, they can be transferred to smaller aquariums."

Regarding tankmate compatibility Wet web media says:

"Engineer gobies are unusual amongst coral fishes in their total lack of antagonism toward other fishes or invertebrates. They will eat very small fishes, crustaceans and worms, but otherwise leave larger-than-mouth size organisms totally alone. Reciprocally, all but the meanest of fishes leave them be, letting “live and let live” with the Pholidichthys residing in their dug out caverns and caves... accepting of almost all food and tank mate situations...It’s only downside is its prodigious digging behaviour, and this is easily checked by careful arrangement of rock work."

Marine Center: "This species is indifferent toward other fish species... Large individuals will eat ornamental shrimps and tiny fishes."

I would really like people's first hand experience's on keeping these fish with seahorses. Or horror stories of their engineer gobies eating other fish would be good also if there are any.