The evolution of animation software tools for computer games and movies opens up new possibilities for animal behaviour studies. With a help of virtual stimuli researchers have the option to conduct standardized and reproducible experiments. While there is no chance of interaction between stimuli and real counterparts yet, Virtual Fish Project at the University of Siegen aims to solve this problem and give virtual fish stimuli the ability to interact with real fish.

We present the first part of the project, in which a novel toolchain to conduct behaviour experiments with Sailfin mollies (Poecilia latipinna) was created. The easy-to-use simulation system offers tools to adapt fish stimuli, record their movement sequences and replay these independently on multiple screens. The whole toolchain is based on free available software.

Core of the toolchain is the fish simuliation tool FishSim, whichrenders the stimuli on the screens. It is based on the game engine Irrlicht. After creating a default stimulus model manually, it can be modified by FishCreator. This tool is based on Blender, a 3D-modelling tool, and offers the possibility to easily change texture, size and fins of a stimulus. Created stimuli can be animated with FishSteering in a user-friendly way with the help of a video game controller. The tool takes care of stimulus' body movements while swimming and records all its actions. There is a chance to adjust bones, fins or gonopodium positions with a game pad, while watching the previously recorded animation. FishPlayer is the last tool in the chain. It offers a separate animation playlist for each screen. Thereby, different animations can be shown on different screens simultaneously. Due to the fact, that all stimuli originate from a default armature model, recorded movement sequences can be replayed with different stimuli.