# Rearing Conditions and Automated Feed Distribution Systems for Zebrafish (_Danio rerio_)
## 5 Automated Feeding Systems
The automatization of the protocols can improve the standardization of feeding management practices and remove manual feeding, which represents the major parameter affecting zebrafish wellness, growth, and reproduction, with a clear lack of control over the delivered quantities [88]. Different feeding regimens and feeding amounts can, in fact, affect growth and reproductive performance in wild-type zebrafish [47] and, as an example, modulate melanoma tumor onset in a p53/BRAF zebrafish line [89], respectively. Moreover, especially in facilities with many tanks, the lack of automated systems leads to the appearance of musculoskeletal disorders among technicians in charge of feeding the reared zebrafish [90]. In recent years, advanced technologies such as machine vision, acoustic technology, and sensor data fusion have gradually been applied to large-scale and refined aquaculture [91; 92]. These technologies might be considered for implementation in the zebrafish rearing and feeding systems. In this context, at the University of Padova (Padova, Italy), a novel automatic dispenser for fast delivery of zebrafish food has been developed and optimized. The so-called multiple fishank feeding doser ([[https://www.knowledge-share.eu/en/patent/multiple-fishank-feeding-doser/](https://www.knowledge-share.eu/en/patent/multiple-fishank-feeding-doser/)]([https://www.knowledge-share.eu/en/patent/multiple-fishank-feeding-doser/](https://www.knowledge-share.eu/en/patent/multiple-fishank-feeding-doser/)), accessed on 4 May 2016) (Inventors: [PERSON] and [PERSON] [93]) (see also [94]) allows for regulation of the amount of food provided according to the fish number, age, size, weight, and experimental setup. In this way, the dispenser avoids the most common problems related to the activity of operators such as overfeeding, which leads to the accumulation of an excess of food at the bottom of the tanks and negatively affects water filters and fish health, or underfeeding, which leads to impaired fish growth and reproductive fitness. The system consists of a small and practice pneumatic device that delivers pulsated amounts of food in one second, thus allowing the administration of a precise amount of food in a precise amount of time to large-scale systems with hundreds of individual tanks. Furthermore, the designed dispenser allows one to save not only food, but also time, as it produces no waste around the feeding hole and, thus, less cleaning is required. This also allows more time available for other husbandry-related tasks, such as cleaning and monitoring. Another interesting solution is presented by the semi-automatic dispenser for solid and liquid food in aquatic facilities developed by [PERSON] et al. [90]. The system represents an intermediate solution between manual and fully automated systems, keeping the assets of both approaches while eliminating most of their drawbacks. The semi-automatic dispenser is battery-powered and portable with a low footprint, able to deliver dry solid or liquid food in a modular manner. It is able to displace all the weight of liquid in a self-supporting reservoir on caster wheels and it does not require a specific operator to trigger and to remain in operation. More importantly, the dispenser can deliver either fixed quantities, operate on controlled quantities, or obtain information on the number of individuals in each tank via near-field communication and automatically deliver the exact amount of food intended. Similar to [PERSON] et al. [90], [PERSON] et al. [95] developed two custom-made open-source semi-automatic and low-cost feeding systems for dry and live food to be implemented in zebrafish facilities. For the delivery of _Artemia_, the system is based on an electric pump capable of sucking live _Artemia_ and delivering them to the housed tanks. The rate of delivery can be adjusted by regulating the pump's speed. The pump is triggered by a sensitive and light-weight button held by the person in charge of feeding.