I have a common goldfish who is 7 years old and I am moving cross country. My initial plan was to take him with me but I won’t be able to put him in his full 15 gallon tank for about a month (we’ll be living with our in laws as we are in the process of buying a house). I have a travel carrier tank (tiny). Would leaving him in that tank for so long be harmful? I don’t know what to do I want to keep him but not if it’s going to hurt him...