My first saltwater tank was an octo tank. Started him in a 20 gallon then moved him to a 30gallon long tank which is not a recommended size... I had little to no experience in saltwater tanks.I kept it alive for 9 months, which is an awesome length of time if you consider that one year is the max you can except to keep one in captivity. And i never made him ink, not once. Keeping the octo happy is the main thing, like giving him hiding spots even though you want to see him all day.... I had a Carribean reef octo, and the most difficult/expensive (unless you live on the coast, which i did) thing to do is have live crabs on hand all the time, and along with that being their main diet you seriously have to feed them a variety, and it really should be live, that would be ideal. You wont see much growth if you dont give them a solid diet, plus watching them eat is awesome anyways, I once bought 100 ghost shrimp from the lfs and when i went to dump a FEW in the tank the bag caught some current and every last shrimp was in the tank. The octopus did not stop until every last of the 100 shrimp were gone, literally, his colors were changing like you wouldn't believe, it was a feeding frenzy and a huge mistake lol, he had a giant ball of wriggling ghost shrimp in his web and was happy as can be... i have some videos and pics of my set up if you wanna see them pm me.. If you want to know more i can certainly help you with any questions, as i learned a lot of do's and donts. they are super fun to keep and arent nearly as difficult as everyone claims.