As stated, these guys really aren't the vicious hunters they're made out to be.
They're actually omnivores (see the quote below), and the tiger pistol (
Alpehus bellulus) is one of two species so far (
Alpheus randalli being the other - see the link in the quote below) that has been confirmed to feed on its goby partner's feces,* so adding a goby may very well help on the off-chance that your shrimp actually is being aggressive:
A quick note here on pistol shrimp diet - pistol shrimp do not seem to be predatory, rather they seem to be more opportunistic, omnivorous scavengers (the only "hunting" that seems to take place outside of the burrow is done by the gobies, not the shrimp, and - to my knowledge - no one has ever confirmed if the shrimp actually eat the "prey" brought to them by the gobies; it might be that the goby eats them rather than the shrimp, or the shrimp might eat them as people generally assume):
link.springer.com
Some more info from the article linked in the quote above:
"Diet analyses of shrimp associates indicate copepods, interstitial matter, and seagrass as main food items. Incidental observations revealed a more varied diet, facilitated by goby associates.
Cryptocentrus cinctus and
C. singapurensis [=
C. leptocephalus] were previously reported to introduce items such as algae and bivalves into burrows for associate shrimps. We observed the goby,
Amblyeleotris latifasciata, capturing a small crab near the burrow entrance and carrying this prey item toward the burrow entrance. Upon arrival, it rapidly moved up and down, a characteristic behavior we can best describe as ‘jumping’. The shrimp emerged from the burrow and proceeded to remove the entire prey item from the mouth of the goby, without resistance or struggle from the latter, before retreating into the burrow (Fig. 1)."
Additionally, as noted in the article linked above, at least some
Alpheus spp. clean their gobies by eating the parasites off of them.
*Source:
