# Increased diameter of arteries and veins in the caudal fins of Danio rerio longfin t2 fish is accompanied by fin overgrowth

## TL;DR

Zebrafish with long fins have larger blood vessels in their tails, which may help control fin size.

## Contribution

The study reveals a link between blood vessel size and fin overgrowth in longfin zebrafish.

## Key findings

- Longfin t2 zebrafish have significantly larger arteries and veins in their caudal fins.
- Increased blood vessel diameter correlates with fin overgrowth in these fish.

## Abstract

The classic dominant
longfin
zebrafish strain (

lof
t2

) has long fins due to ectopic expression of the potassium channel Kcnh2a
in the fin mesenchyme. Potassium channel function is also known to affect the vasculature, but the fin vasculature has not been characterized in

lof
t2

fish. Here we show that

lof
t2

fish contain significantly increased artery and vein diameters in the caudal fin as compared to wildtype fish. Interestingly, these changes in blood vessel size are associated with areas of fin overgrowth, consistent with a possible role for the vasculature in fin size regulation.