All cetaceans (whales, dolphins and porpoises) are capable of communicating underwater using various sound production tactics (clicks, buzzing, singing, bellowing, etc.). Depending on the situation, some sounds can be emitted in strong directional pulses capable of stunning prey, others are semi-directional used for general orientation (echolocation), while others again can be very low and non-directional allowing messages to be carried across extremely vast distances (especially during mating season or when being attacked). The array and types of sounds they can emit is really quite incredible; but yes, sounds produced underwater carry over much greater distances.

However, it's worth noting that they use stocked air to produce these sounds, not water itself. As fish don't stock air like cetaceans and are generally small, they can't really do much to create such loud sounds. But some appear to be able to communicate using rudimentary popping and grunting sounds by vibrating a part near the back of their bodies, flicking their spines or grinding their teeth. As these sounds aren't very strong, they don't carry too far, and they aren't focalized in any way (unlike those of cetaceans) so they travel sporadically all around and get easily drowned by other sounds. It also seems that some fish and other sea-dwelling creatures use bioluminescence to communicate, though you can imagine it only carries a message so far, and representing such a phenomenon in a comic might be a little difficult.