Hi everyone! So we're new to aquarium keeping and i could use some advice please! It all started one rainy day about 2 months ago when my husband brought home a baby painted turtle he found dying in the parking lot of his work. We went right to petsmart for some food and a small house for him (smaller than a quarter) and left with a 40 gallon tank and all the fixins, 10 tetras, 2 albino plecos and a pictus catfish..i felt he needed buddies.Well a week later i felt the pictus needed a bff and also got 2 corydoras. About 1 month ago we were at the park with the pup and found a pond snail a bit bigger than a golf ball and added him/her to the mix. Well baby snails soon followed,we put 7 back in the pond and have 1 baby and mama/daddy still.Last sunday i found my plecos making a ruckus in a decorative shell and today when i did my water change i found a bunch of eggs inside, i left it be but the dad hasn't been around it since.I googled all my critters and learned as much on my own as i can..here's the thing, today my husband found a crayfish (about 1 1/4 in) and decided to add it to our happy tank and i'm very uneasy about it. He found his way to the top of the plants where my little turtle guy (Atreyu) hangs out and i don't like it. He hasn't gone after any of the fish, hasn't done much of anything really but i won't be leaving him in the tank when i go to sleep! Anyway does anyone have any advice on anything? I'm 99% sure Mr. Crayfish will be returning home tomorrow, everyone is healthy, eating,pooping and being goofballs..i lost 2 tetras during my first water change and was terrified..oh also i had 4 of the little see-through shrimp, we lost a 3rd one a few days ago so only 1 now. So any advice would be great, and we are thinking of getting another tank as our brood keeps growing!! Thanks everyone!