I caught them in salt water took them home and put them in the garage. I use one of those plastic storage containers about 50lts but with only about 6 to 8 inches of water in it with aerator. Had about 15 to 20 mullet at the start. I use a fish net to scoop out the crap and have a bucket of tap water beside it every day or two i replace about 1/2 to 1 litre of water. Every other day I feed them usually goldfish food, sometimes bread, cheese, biscuit or nippers broken up small.
When I go out fishing I throw them in the bait tank, so once out they change straight to saltwater and whatever comes back goes back into the container. They survived about 1 month between trips. Only have 2 now the first death was last week. Now it is winter they dont see as much light so I dont know if thats why but I threw in a little bit of pool salt to see if that helps. It entertains me and the kids.
Funny story I was setting up a live bait tank and had the pump recirculating water into a container in the garage which has a painted floor. There was other full buckets of water on the tressels also. I stepped over the mullet container slipping and knocked over the mullet and all the other buckets hurting my foot in the process. We then had 20 mullet jumping around in about 100 litres of water on the floor. I yelled out and my six year old came out her first comment was oh s##t. She helped me pick them up (they were under the boat and amoungst the rubbish) before we had a talk about the swearing.
Would of one funny home videos. Good thing no mates or my wife were there to see it.