Welcome to TONMO! I'm glad you're here -- please let us know more about your endeavor here - what kind of tank is this going into? 75 gal. sounds good (I believe we recommend at least 55). What cohabitants? Our resident experts typically stress the importance of cycling a tank for an extended period (6 months?) before getting a cephalopod... Perhaps this is going into an existing tank... in which case, there's a lot of sensitivity around tankmates.
We have a number of quality articles available for people who are new to ceph-keeping. Also, be sure to use our Search feature - we have about 15 years of content!
The tank was setup for 2 years and then all of the contents were transferred over to a new tank about 7 months ago. The current setup is 75 gallons with a 40 gallon refugium. The fish list includes: large lawnmower blenny, medium watchman goby, yellow tail damsel (until I can catch it), 2.5" skunk cleaner shrimp, bunch of snakehead cowries, turbin snails, and a yellow wrasse (canary or coris it was called).
The critters I am concerned about losing include: cowries, snails in general, and most of all the cleaner shrimp.
So the bobtails are supposed to max out at about 2 inches and seem to stay on the substrate. Is the shrimp going to get attacked?
*edit* I have a large amount of live rock, but I am not sure on the exact pounds. The sand bed is about 3 inches deep.
Cool! Yeah I hear bad things about damsels from others on here (at least with octos) but not sure about the rest of your tank denizens. I don't own a tank myself so can't really offer much advice but others will, I'm sure. The articles should help also... check out the one on tankmates, and the basic articles on cuttlefish keeping. Good luck - maybe start a journal with some pics!
Ok, well through my own experimentation I answered at least part of my question. I will post it here in case anyone is thinking of getting these squids.
I have the squids in quarantine (20 gallon) and figured I could try to see what they would hunt down vs. leave alone.
I put in two fast bait fish (robust silversides) that were just over an inch long which lengthwise were larger than the squid. They didn't even make it 18 hours. Gone without a trace. So in conclusion I don't think any of my fish minus the very large ones would be safe with these squid.
I also added a small hermit crab which is unscathed so far.
You’ve probably discovered the answer to your question about E. scolopes eating your shrimp. I would like to add, putting a Bobtailed squid in a 75 gallon tank it’s likely you would seldom see it. They bury themselves in the substrate, or in the LR in your case, and only come out at night. Can that change? Maybe. Anything is possible with training.