PROBLEM TO BE SOLVED: To provide a structure that can be easily built up even by one diver in the sea and suitably according to the geographical features etc. of a site and that does not make fish and shellfish alert while being easy for algae and seaweed to grow.SOLUTION: This fish reef block is easy to stabilize even at the bottom of the sea in a horizontally connected state because of having a polygonal base at the bottom face. The fish reef block can be extended stepwise because of having a vertical connecting means at the upper face center of a center protrusion that rises at the center. Each side of the base is provided with a connecting means for connecting the adjacent base, and angular parts between the respective sides, which are pointed in shape and weak in strength, of the base are eliminated. Because the angular parts are eliminated, through-holes for the fish and shellfish to move up and down are formed when a large number of fish reef blocks are horizontally connected. Anchors are further provided for fixing required parts to the bottom of the sea when the fish reef blocks are installed and built up at the bottom of the sea.【課題】海中で一人の潜水士でも容易に、かつ現場の地形などに応じて臨機応変に組立てることができ、しかも魚介類が警戒せず、また藻や海藻が育ち易い構造を実現する。【解決手段】漁礁ブロックは、多角形の基盤を底面に有しているので、水平方向に連結した状態では、海底でも安定し易い。また、その中央に立つセンター凸部の上面中央には、上下方向の連結手段を備えているので、段状に拡張できる。そして、前記基盤の各辺には、隣接する基盤同士を連結するための連結手段を有しており、基盤の形状的に尖っていて強度の弱い、各辺間の角部を無くしてある。従って、水平方向に多数連結した際に、角部を無くすことで、魚介類が上下動するための貫通孔が形成される。漁礁ブロックを海底に設置し組立てた際に、要所を海底に固定するためのアンカーを備えている。【選択図】図１
