Wheeler's Goby Aggression...

[archerhoops]

So I have a 32g Biocube stocked with a yellow banded possum wrasse, a skilletfish, and most recently a Wheeler's goby (+ tiger pistol shrimp). The Goby/Shrimp were added just over a month ago and are both pretty close to their full size. I didn't really notice any problems initially. The goby was definitely an energetic feeder, occasionally darting towards the suspended food in the water column and charging the wrasse, but I didn't think much of it at the time.

Anyway to get to the point, this past weekend I was away and when I went to feed the tank last night, I noticed my possum wrasse had some strange markings that appeared to me to be bite marks. Even after feeding, I noticed some aggression by the goby while the wrasse was swimming around picking at the rocks. The good(?) thing is that the wrasse isn't displaying any signs of stress. His coloration and behavior both seem normal and he hasn't played dead or anything. I'm just so surprised and disappointed, by all accounts wheeler's gobies seem to be really peaceful so I'm not sure what I'm doing wrong here.

I guess my questions are does it sound like I may be doing anything wrong? This is my first saltwater tank and it's less than a year old, so I'm not super experienced. Is there anything I can do to minimize this aggression aside from removing the goby? If I do have to remove the goby, any tips on going about that? and for the sake of the pistol shrimp, any suggestions on a more peaceful goby?

 

[KrisReef]

Classic question, with a great twist on the focus of 'wrong' doing.

The easiest thing to not comprehend, from our perspective, may be the size scale of our tanks compared to the ocean where our fish used to live?

The classic behaviorial experiment(s)~ Over Crowding Rats In Captivity lead(s) to the observation of aggression and cannibalism. The normal footprint of a goby's ocean floor space is likely to be 10 square feet, or greater. I suspect that the goby is just defending the 32 g biocube's substrate as all of it's comfort zone, as a normal thing.

Most folks overstock compared to oceanic space allocations, imo. Post up a picture of your tank and a lot of folks will say you can "add another fish" safely. Your current observation should tell you otherwise, if you want to reduce stress and aggression among your fishes.