of each tray are connected to a down spout arrangement that flows water downwardly via drain holes disposed in the tray of each level capability to hold different sized tanks and use tank dividers is also disclosed application_number US 20404098 A description with reference to fig1 through 3 there is provided an aquatic housing system generally represented by numeral 20 aquatic housing system 20 includes a frame or rack 30 a plurality of housing levels 40a 40b and 40c a plurality of fish tanks 21 and a water drainage assembly 80 rack 30 includes four vertical corner posts of which front corner posts 31 and 32 are shown in fig1 and portions of rear corner posts 33 and 34 are shown in fig3 rack 30 also includes a plurality of side members that connect corner posts 31 and 33 at each housing level 40a 40b and 40c only one such side member 35 is shown in fig3 rack 30 also includes a plurality of side members that similarly connect as by bolts not shown corner posts 32 and 34 at each housing level 40a 40b and 40c only one such side member 36 is shown in fig3 left hand corner posts 31 and 33 are connected to right hand corner posts 32 and 34 by a top cross piece 37 and a bottom cross piece 38 bottom cross piece is shown in broken form in fig1 corner posts 31 through 34 and side members 35 and.