Here is just a technical comparison to show how simple it is to change an image using digital technology. The image at the top has no green stripes in it. I remembered that blue makes the image recede i.e dark blue is used to paint the horizon - never black!!!
This an image of some of  my favourite fish - Neon Tetras I love the shiny bright stripes on them. The other fish was like one we saw at our visit to Dobbies!! I liked the bright colours - aquariums are great as you can find so many interesting activities going on in them!
 Recently we had a class lesson with Primary twos and threes -  in which the pupils made their own fish using sponge or hand printing. Then they made an aquarium background using collage on which to place the fish.  This lesson ties in with biology and the social side -  if the pupils are able to go out and see a real fish tank.. I know that some pet shops have lovely fish tanks and pupils love to visit. The topic could lead onto pupils inventing and investigating  sea creatures to place in their tank. I was able to obtain large plastic envelopes which were used to put the painted collage in and viola!! Your own fish tank!