Intra and inter specific aggression in aquarium kept

Intra- and inter- specific aggression in aquarium kept Cochu’s Blue Tetra (Knodus borki) Bahia Groenewald Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag X 17, Bellville 7535 bahiagroenewald@gmail. com

Introduction Classification ØKingdom: Animalia ØPhylum: Chordata ØClass: Actinopterygii ØOrder: Characiformes ØFamily: Characidae ØGenus: Knodus ØSpecies: K. borki Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Introduction ØNatural range: Amazon Basin (South American Rivers, Peru) ØDescription: Compatibility and recommendation; shoaling ØSpawning www. myperuboliviatours. com Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Introduction ØAggressive behaviour is a term used to cover aspects of fighting, since no simple distinctions are between the initiation of a fight, attack and retaliation or defence. ØIn an attempt to organize various aspects of aggressive behaviour into discrete categories, 3 main criteria arise: ØSituation in which behaviour is shown ØThe functions it serves, and ØIts motivational basis. ØThe relationship between intra and inter specific aggression: ØIntra-aggression is between members of the same species Ø Inter-aggression is between members of different species Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Study aims v. To establish if Knodus borki is aggressive both within species and between species when kept in hobbyist aquariums. v. To determine if aggression levels can be ameliorated. Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Research Questions 1) Does shoaling make an individual more aggressive ? 2) Are they more aggressive in larger shoals? 3) Is intra-specific aggression related to size and sex of fish? 4) Is there more intra-specific or more interspecific aggression in Knodus borki? Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Hypotheses 1) Fish are less aggressive in larger shoals 2) Normal aggression in this species will be displayed almost exclusively to conspecifics 3) In small or crowded aquaria, K. Borki will get frustrated and likely become aggressive towards other species of fish Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Methods ØExperimental fish: Knodus borki is kept in a single species tank for the purpose of intra-specific aggression study. ØFor the purpose of inter-specific aggression study, another species of fish (preferably shoaling species) will be added to the tank (the species for this is not yet determined). ØFish will be filmed, for a duration of two weeks for 20 min twice a day(one week each for intra- and inter-specific analyses), and observed behaviours will be recorded respectively. Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Methods Behavioural observations Darting behaviour & Aggression Darting: where fish are being chased or just swimming around Aggression: based on the total number of attacks and chases within the tank Shoaling: is known to reduce aggression in many species, and lack of this can increase aggression Adapted from: Saxby et al. , 2010 Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald

Acknowledgements I would like to thank Dr. Knight for his guidance and support Honours Science Methodology Project Proposal Seminar: BCB Dept. 23 rd Feb 2011_ Bahia Groenewald