The fish muscle growth is not lineal and occurs through a combination of recruitment of new muscle fibers (hyperplasia) and an increase of the size of existents fibers (hypertrophy) in post-juvenile stages
(Johnston 1999; Mommsen 2001). In contrast to other fishes, zebrafish have determinate growth, the number of muscle fibers is established and fixed at the time of the birth; and growth is solely due to hypertrophy of fibers already formed (Du 2004). This condition does not provide a general model for muscle growth since it only reaches a modest ultimate body size (3–5 cm) (Johnston 1999; Mommsen 2001).
The average weight and length at 4, 12 and 20 weeks measured by Ulloa et al. (2011), are 3.5; 74.9; 213.4 mg and 6.4; 15.3; 21.3 mm, respectively.
(Drawn from the article by Ulloa et al. (2011): https://www.researchgate.net/publication/225767025)
Max length : 3.8 cm SL male/unsexed (http://www.fishbase.org/summary/4653)
For more reffer:
Talwar, P.K. and A.G. Jhingran, 1991. Inland fishes of India and adjacent countries. vol 1. A.A. Balkema, Rotterdam. 541 p
Article Zebrafish as a model organism for nutrition and growth: Towa...