# Rearing Conditions and Automated Feed Distribution Systems for Zebrafish (_Danio rerio_)
## 5 Automated Feeding Systems
On the other hand, the delivery of dry feed in the form of granules is based on a system using standard electronic components. Food delivery can be triggered using three different methods to avoid repetitive movements. These are two sensitive buttons close to the natural proximity of the fingers and contact sensors which are activated as soon as the device is in contact with the lid of the housed tank. [PERSON] et al. [96] have coupled an automatic feeding system to a Noldus EthoVision video-tracking system able to control the production of obese zebrafish by applying a short-term overfeeding period protocol and analyzing the metabolic changes during aging and overfeeding. Moreover, automated feed distribution allowed [PERSON] et al. [97] to develop an automated apparatus for rapid zebrafish conditioning paradigms using Arduino microprocessors. This system allows for control of the delivery of auditory or visual stimuli to groups of different aged zebrafish (juveniles or adults) reared in their home tanks in a conventional facility. After the conditioned stimuli, precise amounts of food are administered through an automatic feeder, and the responses are recorded using video cameras and analyzed using the software ImageJ ([PERSON], [PERSON], National Institutes of Health, Bethesda, MD, USA) or Matlab (The Mathworks Inc., Natick, MA, USA). Unlike [PERSON] et al. [90] and [PERSON] et al. [95], the solution Zebrafish Automatic Feeder (ZAF) developed by [PERSON] et al. [98] represents a fully automated solution for feeding. The basic operating principle of ZAF is very simple: it consists of a servo motor that rotates a food canister to dispense food into a container directly filled with water. The food-water mixture is then distributed to the tanks using pumps and a manifold tubing system. The ZAF system consists of three main modules: (i) electronics, (ii) tubing and pumps, and (iii) food preparation which synergistically allow for a constant amount of food to be delivered in all tanks and to modify the dosage by adjusting the food container opening as well as the degree of servo rotation. The system provides standardized diets to all the housed tanks, is cost-efficient, and easy to build. Furthermore, the advanced version of ZAF, called ZAF\({}^{+}\), also allows a precise control of food distribution and a function of fish density per tank. In this context, a further contribution is given by the automated feeding system called Tritone, designed and produced by Tecniplast S.p.A. (Bugugugiate, Varese, Italy) (Inventors [PERSON] and [PERSON]) [99]. The Tritone is a robotic system able to deliver multiple dry diets (up to four different diets), different in granulometry and composition, as well as liquid diets (generally containing _Artemia_ nauplii). This solution represents a suitable approach for feeding experiments, since the flexibility to test different diets in a standardized manner is allowed, thus avoiding the variability introduced by the operators. The dosing device, in fact, is equipped with an automatic coupling and release means that alternatively retain or release a pin solidly associated with the container bottle. The spout of the dispenser is located close to the feeding hole in order to get a highly efficient food deliver. Different diet granulometries are provided by different diameters of the spout connected to the dispenser, and particle sizes up to 600 \(\upmu\)m do not affect feed delivery. The tank-specific automated food administration is allowed by special codes located at the bottom of the tanks where all information is coded. Thus, the operators can determine and schedule specific diets for specific tanks housed in the facility according to their precise requirements. Feeding time(s) and feeding ratio(s) can also be decided by the operators. Moreover, the system is supplied with a video camera housed directly on the head of the dispenser so as to remotely control correct operation and, in particular, correct positioning of the dispensing system.