A simple night-day light simulator [for fish culture]

actividad solar acuicultura alimentos animal animal aquatique animales animals aquaculture aquatic animals aquatic organisms aquiculture behaviour comportamiento comportement darkness energia energie energy energy sources fish culture fishes foods inanition light luz natural resources nutrition obscuridad organisme aquatique peces physical states piscicultura pisciculture produit alimentaire radiation recursos recursos naturales resources ressource ressource naturelle solar activity starvation vertebrados vertebrates vertebre