Effects of Formalin on Length and Weight of Fishes

Journal of the Fisheries Research Board of Canada 04/2011; 20(6):1441-1455. DOI: 10.1139/f63-098


Sockeye smolts, pink and chum fry, and pink and chum fingerlings (Oncorhynchus) were sequentially weighed and measured when alive and after death in water and after killing and storage in formalin up to 225 days. The fish shrank within 12 hours to 97% and by 30–40 days to 96% of live length. Further changes in length were not significant. These same relative changes were observed from fish of different sizes, and the values were not significantly different among groups preserved in formaldehyde solutions of fresh or sea water. In fresh water, fish gained weight while yet alive but under anaesthesia. In freshwater formalin, fish gained weight rapidly for 1 or 2 days, then lost weight at a decelerating rate to the time of last measurement. Fish killed and stored in salt water formalin lost weight for the first few days, then gained weight at a decelerating rate. Relative magnitudes and rates of change were inversely related to size of specimens contained in the sample. These changes had pronounced effects on relative condition factors which varied from 97 to 135% of live values depending upon size of fish, type of formalin and time in preservative.

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    • "Several authors have studied the effects of formaldehyde on fish eggs, larvae and adults (Parker, 1963; Rosenthal et al., 1978; Billy, 1982; Hay, 1982; Kristoffersen and Salvanes, 1998; Xiong et al., 2007). Shrinkage of formalin-preserved larval fish varies among species (Schnack and Rosenthal, 1978). "

    Journal of Applied Ichthyology 04/2015; 31(2). DOI:10.1111/jai.12678 · 0.87 Impact Factor
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    • "According to the Guidelines for the Use of Animals in Behavioural Research and Teaching (Anon, 2006), anaesthetics should be applied for ethical reasons , but in order to examine whether they hinder the size or shape analysis, their effect had to be studied and considered. As noted above, it has been suggested by Parker (1963) and Theilacker (1980) that MS-222 interferes with osmoregulation, and therefore can contribute to the shrinkage of live larvae. Additionally, in Methot & Kramer (1979), Theilacker (1980) and other comparative studies on the effect of fixatives such as by De Leon et al. (1991), it was not used. "
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    ABSTRACT: This study established an optimized protocol for quantifying the shape variation of newly hatched larvae of European seabass Dicentrarchus labrax, focusing on the effect of fixatives and mounting on body shape from hatching until 14 days post hatching, while also minimizing the error introduced by handling. This assessment was performed based on both biometric and geometric shape data, with the latter relying on outline based elliptic Fourier analysis. The fixation and mounting effect on the total length and shape of newly hatched larvae of D. labrax was tested for four fixation treatments: (1) 8% formalin, (2) 70% ethanol, (3) 8% formalin for 48 h and then to 70% ethanol and (4) 3% phosphate-buffered glutaraldehyde. The analyses showed that no significant size and shape effect was observed on anaesthetized specimens 5 months post-fixation in glutaraldehyde, and that the glycerol mounting process of specimens fixed in glutaraldehyde provided the best results for further ontogenetic qualitative and quantitative analysis. The protocol proved to be sufficiently sensitive to even quantify and visualize subtle pre-fixation shape differences originating from a different egg batch.
    Journal of Fish Biology 01/2014; 84(1):206-24. DOI:10.1111/jfb.12284 · 1.66 Impact Factor
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    • "Results of present study showed total length of samples fixed in formalin reduced than fresh fish that probably due to wrinkle and shrinkage of the body and egress of interstitial water during of preservation in 10% formalin. Also, our results are confirmed by the findings of some researchers such as Lux (1960), Parker (1963), and Engel (1974). In addition, Jawad et al. (2001) revealed that different concentrations of formalin and alcohol on one hand and freezing on the other caused variable degrees of shrinkage of the three characters studied (SL, TL, HL). "
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    ABSTRACT: Formalin is one of the important fixator in fish studies, and has many effects on morphological indices of fishes, so in this study the effect of this fixation was examined. The present study was done to investigate the effects of fixing and preserving in 10% formalin on the morphological characteristics of goldfish (Carassiusauratus). For this aim, 30 specimens of goldfish were collected from the Researches Center of Aquaculture, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. After initial evaluation on morphological characters such as Total Length (TL), Standard Length (ST) and Head Length (HL), samples were fixed and preserved in 10% w/v formalin for 11 weeks. After this period, samples were removed from formalin and measurement and evaluation of color features were done once again. The results showed shrinkage was common in all of the specimens and changes in body color were clearly distinguishable with fresh fish such a way that the body and fins color were opaque but color pattern is acceptable but the intensity is reduced.
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