Types of Overflows:

Custom Fish Tank With external Overflows By Aqua , Creations, Huge fishtank

In the world of aquascaping, custom fish tanks have emerged as a popular choice among enthusiasts. These tanks offer unparalleled flexibility in design and functionality. One critical aspect when designing your custom fish tank is the placement of the overflow box. This guide will take you through the ins and outs of overflow boxes and their strategic placement in different tank styles.

Understanding Overflow Boxes:

Overflow boxes serve a vital role in maintaining the health and clarity of your custom fish tank’s water. They act as a barrier between your display and the drain pipes, reducing the chance of your fish getting trapped in the pipe. The overflow box allows water to flow over the top of the tank and into the sump when the water level reaches the top. This regulation of surface water prevents overflowing and increases filtration capacity.

Overflow boxes come in two main types – internal and external. Internal overflows are placed inside the tank, but can limit swimming space and a bit more noticeable. External overflows maximize interior space, totally out of sight and provide easy access to plumbing but require very careful planning and installation.

Overflow Box Placement in Different Tank Styles:

The placement of the overflow box depends on your custom fish tank style:


Peninsula Style: Ideal for viewing from three sides, the overflow box should be at one end and can be built with internal or external overflows.  


Island Style: For tanks viewable from all sides, depending on the size of the custom fish tank, internal overflow with center placement ensures efficient water circulation without obstructing views.


Front View Style: For traditional front view tanks, rear corner or center back placements are optimal. Internal or external are possible.


Front and Back View Style: In this case, side wall placement keeps the overflow out of sight from the primary viewing angles. Typically external is more pleasing however the space would need to allow for that.

Types of Food


Custom fish tanks offer a unique opportunity to create a thriving aquatic environment tailored to your needs. The overflow box, while often overlooked, plays a crucial role in maintaining a healthy and esthetically pleasing aquarium. Understanding its purpose and optimal placement based on your tank style can significantly enhance your custom fish tank’s design and functionality.


We’d love to hear about your experiences with custom fish tanks and overflow boxes. Feel free to reach out to us.