PROBLEM TO BE SOLVED: To provide a background parts accommodating device that can be enlarged or reduced in proportion to the size of an ornamental water tank. SOLUTION: A background part housing device for an ornamental aquarium has a pair of left and right background image sheet holding frames 3 and a base frame 2A that can extend in the left and right directions of a base frame 2A made of a rectangular frame. It is provided with a water tank upper end connecting rod 4 for fixing to a possible left and right pair of water tank upper ends, and a left and right pair of left and right bottom plate holding connecting rods 5 for extending downward of the base frame 2A. Therefore, the background part housing device can be expanded vertically and horizontally depending on the size of the aquarium. Then, the three-dimensional background parts are placed on the bottom plate 7 fitted on the bottom plate holding connecting rods 5, the background image sheet 6 is fitted on the holding frame 3, and the background part accommodation device is attached to the back of the water tank. If you look at the fish you watch from the table, you can see through the three-dimensional parts and the background image behind them, increasing the aesthetic value of the aquarium. [Selection diagram] Figure 2【課題】観賞用水槽の大きさに比例して拡大、縮小できる背景パーツ収容器具を提供する。【解決手段】観賞用水槽の背景パーツ収容器具は、方形をした枠体よりなるベース枠２Ａの左右方向に延伸可能な左右１対の背景画像シート保持枠３、ベース枠２Ａの上方向に延伸可能な左右１対の水槽上端に固定するための水槽上端結合棹４及びベース枠２Ａ下方向に延伸可能な左右１対の観賞用パーツ載置用の底板保持用結合棹５を備えている。従って、背景パーツ収容器具を水槽の大きさに応じて上下左右に拡大できる。そして、底板保持用結合棹５の上にはめ込んだ底板７の上に立体的な背景パーツを乗せ、背景画像シート６を保持枠３にはめ込み、この背景パーツ収容器具を水槽の後ろに取り付け、水槽の表から鑑賞魚を鑑賞すると立体的なパーツとさらにその後ろに背景画像が透視でき、観賞用水槽の美的価値を高めることができる。【選択図】図２
