A modular apparatus and system for managing the temperature of a livewell or other container housing water, and an associated method for installing the same. The system featuring a self-contained fluid line in communication with a first fluid line, which is in fluid communication with the livewell. The system further can comprise an output module capable of outputting a signal related to the system. The modular apparatus generally featuring the system and an enclosure. The enclosure may comprise a user interface and be capable of being located in areas with limited available space. The enclosure can be located adjacent the livewell and detachably coupled to a fishing vessel. The modular apparatus and system can further comprise a condenser, which can be a forced air coil unit, a liquid-cooled unit, or a cold plate heat sink unit. The method of installing generally comprises removing existing livewell hose and providing the system.
