I've been a frequent viewer of this website and community but just made an account, I have seen hundreds of posts and discussions. One that particularly caught my eye was some discussions on Sleeper Goby's such as the Marble Goby and the Water Cow. I've spent some time looking at these fish and have found them to be almost perfect in the type of fish I wish to care for. I can currently accommodate many of its needs (meaning that I would still have to acquire the rest of the resources) however, I am looking into the tank size. I currently have a 40 gallon breeder from Petco (36" x 18"). I can also care for the other needs (food, water changes, substrate, and décor). While I could and will upgrade to a larger tank size if nessecary, I am wondering if anyone knows of any other fish such as the Water Cow or Marble Goby that may be smaller. I also am wishing to know which of the two are larger and what is the absolute minimum size for the tank? I still have a bit to research before possibly buying this fish but I may just need some more info.