A fun kawaii cute joke on the pun of kitty / kit-tea. A glass tea cup, with a tea bag and a few fish inside making it look a bit like a fish bowl, with a kitten behind the tea cup looking in.
Where you can buy online
TeePublic (US and UK)
RedBubble (US)
Design By Humans (US)
Threadless (US)
NeatoShop (US)
You can find the design on t-shirts in most stores, but also on other products depending on the store (e.g. hoodies, mugs, stickers, notebooks, phone cases, greeting cards, cushions, socks etc).