I just wanted to add something to Pete’s wonderful response….
Unfortunately 5 gallons is much to small a tank for either a Scooter Blenny or a Jawfish. Both have special needs that cannot be met in a tank that size.
Please do have a look at the following articles for more info on
Scooter Blennies http://www.wetwebmedia.com/mandarins.htm
Best od luck with your little girl.