(Please see the attached PDF with photos of the basic supplies that might help you gather the best materials for this class.  However, please understand that the photo shows a white canvas instead of the black one that is needed for this specific lesson.)

1 BLACK SURFACE SUITABLE FOR ACRYLIC PAINTS:
8" x 10" BLACK Canvas (the type that has primed [coated BLACK] canvas stretched over a wooden frame & stapled to the wood on the back is my preferred type - you'll also be able to find some that are stapled to the side of the wood frame. Other options listed below would work well, too.)

OPTIONS instead of the 8" x 10" BLACK Stretched Canvas listed above:
8" x 10" BLACK Canvas Panel or Canvas Board  (It will not be as thick as the stretched canvas and will feel more solid like the canvas is mounted/glued to a stiff cardboard.)
OR an 8" x 10" piece of BLACK Acrylic Canvas Paper that usually comes in a pad of multiple sheets.
OR cut a BLACK Foam Board down to 8" x 10"
OR buy a White Canvas or Canvas Panel and Paint it Solid Black with Acrylic Paint at least 1 day before our class so that it has plenty of time to dry completely before your child uses it in our class.  
[Please Note:  If your child brings a white surface instead of a black surface to paint on, he/she will still be able to participate in class but will just learn some of the tips by watching my demonstration instead of trying it themselves.  There will also be more background area to finish painting after class ends.]

ACRYLIC PAINTS:   (not tempera, watercolor or oil)
Each child will need WHITE, BLACK, YELLOW, ORANGE & possibly RED for this fish.  However, a variety of other colors will be best for the background such as Blue, Green, Purple, Brown.  Store brands in tubes are a good consistency.  (If you need to reduce the number of paints you purchase, be sure to have Blue, Red, Yellow, White & Black since many other colors can be mixed using those.)

PAPER PLATE to use as a paint palette (or a plastic paint palette if you already have one)

ACRYLIC PAINT BRUSHES in a variety of sizes.  Include a couple of ROUGH Flat Brushes - a medium & a small one (looks like a square on the tip but bristles are rough and a little prickly to the touch.  Also include a couple of very small SMOOTH Acrylic Brushes (1 very small Round brush like a pencil tip shape and 1 slender Flat Square Shape)

WATER in a metal can, plastic cup or glass jar.

PAPER TOWELS