The scientists observed that the tetras that normally spend time in the light do sleep soundly at night, resting on the bottom of their tanks.
科学家观察发现，接触阳光时长正常的鱼类在晚上会在鱼缸底部睡得很安稳。
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Angelfish are an easy - to - keep cichlid species. they should not be kept with neons or cardinal tetras, though, as these tetras are a delicacy for the larger angelfish.
Visiting Jem Aquatics shop I saw some pretty young Cardinal Tetras from a recent shipment. The fish were in excellent condition, of good shape and young, just ready and promising.