Temperature is a key environmental factor affecting the growth, metabolism, and survival of teleost fish. Epinephelus akaara, a warm-water marine species of high aquaculture value, is particularly vulnerable to low-temperature exposure during overwintering culture. Therefore, clarifying its hepatic metabolic responses to cold stress is very important for understanding low-temperature susceptibility and improving aquaculture management. In this study, E. akaara were exposed to four temperature treatments 25 °C, 20 °C, 15 °C and 10 °C for 10 d, and the effects of low temperature on physiological status and hepatic metabolic profiles were evaluated by integrating serum biochemical, enzymatic, and ionic indices, hepatic Oil Red O staining, and widely targeted metabolomics. The results showed low-temperature exposure altered serum glucose levels, lipid-related indices, transaminase activities, and ionic balance, and was accompanied by increased hepatic lipid deposition. The proportions of lipid droplet area were 1.21%, 11.17%, 14.88% and 16.74% in the 25 °C, 20 °C, 15 °C and 10 °C groups, respectively. Compared with the 25 °C group, 457, 295, and 333 differential metabolites were identified in the 10 °C, 15 °C and 20 °C groups, respectively, of which 138 were shared by all three low-temperature groups. These metabolites were mainly enriched in pathways related to amino acid metabolism, lipid metabolism, bile acid metabolism, substance transport, and stress signaling. Low-temperature exposure significantly reshaped the hepatic metabolic network of E. akaara. These findings provide metabolic evidence for understanding the response of warm-water marine fish to low-temperature stress and offer a basis for low-temperature culture management, overwintering risk assessment, and future studies on cold acclimation in aquaculture.

Sepiella japonica is a cephalopod of significant commercial value, commonly found throughout China's coastal waters, ranging from southern Hong Kong to the Korean Peninsula and western regions of Japan. However, under captive conditions, S. japonica frequently exhibits precocious sexual maturation, which can result in reduced adult body size and severely limit aquaculture development. Therefore, elucidating the molecular mechanisms on ovarian development has become a critical priority. In this study, RNA sequencing was performing of the ovary tissue of female S. japonica collected across four key ovarian developmental stages: oogonium production (stage I), protoplasmic growth (stage II), interstitial growth (stage III), and trophoplasmic growth (stage IV). A total of 354,393,214 clean reads (Q20>98.58%) were obtained from 16 samples. Pairwise comparative analyses of I vs II, II vs III, and III vs IV identified 10050, 2564, 2278 differentially expressed genes (DEGs), respectively. Through differential expression analysis, we identified 13,319 differentially expressed genes (DEGs), among of which exhibited consistently high expression across four developmental stages, such as FOXL2, HSD17B2, and BMP1, suggesting their critical roles in regulating ovarian development in S. japonica. Gene Ontology (GO) enrichment analysis showed that these DEGs were significantly enriched in processes including protein targeting to the ER, response to estradiol, oxidative phosphorylation, and female pregnancy. KEGG pathway analysis revealed that DEGs were significantly enriched in key functional pathways, such as Ribosome, Prolactin signaling, FOXO signaling, and Lysosome. Furthermore, the “response to estradiol” pathway was consistently enriched across multiple developmental stage comparisons, suggesting that genes associated with steroid-related signaling may play conserved roles during ovarian development in S. japonica. This study clarified the regulation of transcript expression and molecular mechanisms in the ovary of S. japonica at different ovarian development stages, thereby offering theoretical guidance for enhancing reproductive efficiency in mollusk aquaculture.

This study explores the molecular responses underlying the FOXO/MAPK signaling pathway’s regulation under cold stress in Epinephelus akaara. Using transcriptome sequencing and RT-qPCR analysis, this study elucidates how E. akaara maintains energy balance, immune function, and cellular repair through the regulation of FOXO and MAPK signaling pathways under cold stress. The results demonstrate that several genes involved in energy metabolism and cellular homeostasis regulation, including FOXO1, SGK2, and G6PC, exhibit significant temperature-dependent changes, highlighting the crucial role of these pathways in cold adaptation. The study further reveals that under the suppression of the FOXO pathway, the MAPK pathway compensatorily activates to sustain stress sensing and repair functions, illustrating a multi-pathway signal integration response. Additionally, the expression changes of heat shock proteins further support the cellular adaptation strategies to cold stress. Overall, this study offers a novel molecular perspective on understanding the cold adaptation responses in E. akaara, provides theoretical support for cold-resistant breeding and cold stress mitigation strategies, and lays the groundwork for the sustainable development of the aquaculture industry.

This study aimed to investigate the molecular responses underlying the adaptation of Epinephelus akaara to low-temperature stress. Using transcriptome sequencing, antioxidant enzyme assays, and histopathological examination of the liver, this study evaluated the physiological, metabolic, and molecular responses of E. akaara to different temperature conditions 10 degrees C, 15 degrees C, 20 degrees C, and 25 degrees C. The results demonstrated that low-temperature stress triggered oxidative stress, resulting in the accumulation of lipid peroxidation products in the liver and the activation of several key signaling pathways, particularly the PPAR pathway, which plays a critical role in regulating lipid metabolism and maintaining energy homeostasis. At 20 degrees C, the antioxidant system of E. akaara showed the greatest stability and minimal oxidative damage, whereas at 10 degrees C and 15 degrees C, oxidative stress was more pronounced, accompanied by a significant increase in lipid peroxidation products. These findings provide novel molecular insights into the low-temperature adaptive responses of E. akaara and offer theoretical guidance for improving cold tolerance and optimizing aquaculture management.

Effectively assessing the basic genomic information of a species is fundamental for conducting molecular research and provides a foundation for constructing whole-genome maps. Hapalogenys analis is a temperate and tropical nearshore marine fish in China’s coastal waters, with significant economic value and high aquaculture potential. However, the genomic differences between male and female individuals of this species are not yet apparent. This study conducted whole-genome survey analyses on male and female H. analis to provide basic genomic information. According to K-mer analysis, the genome sizes of female and male fish were 436.24 Mb and 493.21 Mb. The heterozygosity rates were 0.58% for females and 0.23% for males. The proportion of repetitive sequences of female and male fish were 42.95% and 51.20%. The GC content of the genomes was 43.30% for female and 43.20% for male. The sizes of the assembled genomes were 589.18 Mb for female and 592.02 Mb for male, with N50 lengths of 3,135 bp and 3,041 bp, respectively. SSR screening results showed that 959,447 and 894,158 SSR sequences were detected in the genomes of female and male, respectively. The lengths of the assembled mitochondrial genome sequences were 19,755 bp for female and 19,754 bp for male, each containing 38 genes. Among these mitochondrial sequences, 13 protein-coding genes were identified, including 7 NADH dehydrogenase, 3 cytochrome c oxidase, 1 cytochrome b, and 2 ATP synthase genes. Both sequences contained 23 tRNA genes and 2 rRNA genes. This study provides a theoretical basis for constructing a high-quality whole genome of H. analis and valuable data for subsequent molecular breeding research.

The genus Hapalogenys was one of the most controversial and problematic issue about its phylogenetic position in Perciformes. In this study, the complete mitogenomes of three Hapalogenys species and other five closely related species belong to the same order Lobotiformes were compared. The general sequence characteristics are identical to that of most teleosts, including sequence length, nucleotide content, codon usage frequency and gene arrangement; while the newly sequenced Hapalogenys analis in this study lacks a canonical tRNA-Pro. Two major non-coding regions, the light strand replication origin (OL) and control region (CR) were compared in detail. All OL region were able to form typical stem-loop structures, despite H. analis was obviously shorter in the OL region. Although CR has the fastest evolutionary rate among mitogenome, several conserved structures were found, including the termination associated sequence (TAS), the central conserved blocks (CSB-E, D, and A) and the conserved sequence blocks (CSB-1 and 2) except in H. analis. Both ML tree and BI tree revealed that Hapalogenys genus clustered into a clade and formed a sister group to Datnioididae, supporting the non-Haemulidae relationship of the Hapalogenys group and suggesting its ‘traditional’ place within the Haemulidae is incorrect. These results will not only clarify the mitogenome features of Lobotiformes, but also lay a foundation for further understanding the phylogenetic relationships of Perciformes.

Hapalogenys analis (order Lobotiformes) is an economically and ecologically significant fish species. It is a typical sedentary rocky reef fish and is primarily found in the northern Pacific Ocean. Here, we used Hi-C and PacBio sequencing technique to assemble a high-quality, chromosome-level genome for this species. The 539 Mb genome had a contig N50 with a size of 3.43 Mb, while 755 contigs clustered into 24 chromosomal groups with an anchoring rate of 99.02%. Of the total genomic sequence, 132.74 Mb (24.39%) were annotated as repeat elements. A total of 21360 protein-coding genes were identified, of which 20787 genes (97.32%) were successfully annotated to public databases. The BUSCO evaluation indicated that 96.90% of the total orthologous genes were matched. The phylogenetic tree representing H. analis and 14 other bony fish species indicated that the H. analis genome contained 364 expanded gene families related to olfactory receptor activity, compared with the common ancestor of H. analis and Sciaenidae. Comparative genomic analysis further identified 3584 contracted gene families. Branch-site modeling identified 277 genes experiencing positive selection, which may facilitate the adaptation to rocky reef environments. The genome reported here is helpful for ecological and evolutionary studies of H. analis.

Microplastics (MPs) are a global concern regarding environmental pollution. This study evaluated the impacts of MPs with two sizes (5 µm and 0.5 µm) on hatching performance and microbiota of Sepiella japonica . The presence of MPs increased the hatching rate at some stages of the fertilization process and reduced the oxygen consumption rate at the gastrula stage. No size-dependent impact was observed. The 16S rRNA gene was sequenced to identify the flora. Clustering tags assessed species diversity in the samples with 97% similarity. Proteobacteria was the most abundant phylum in all three groups. MPs publicity appreciably modified flower structure. The most variable genera were Ralstonia, Methylophilus, and Pseudorhodoferax, which can furnish nutrients and modify the host’s immune response. MPs exposure appeared to enrich beneficial bacteria in this study. The presence of MPs with a size of 5µm played a greater role in this process, which is supported by presumptive functions. However, since the adsorption of suspended MPs on aquatic eggs can have cascading effects on specific life stages of oviparous animals, regular monitoring of microbial communities is necessary after juvenile S. japonica formation to prevent disease outbreaks.

To clarify the influence of different water temperatures on the development of Portunus trituberculatus (swimming crab) larvae during off-season (early autumn) breeding, a gradient of four rearing temperatures of 27, 29, 31 and 33 degrees C was setup, and the effects of water temperature on larval development were systematically compared. The results showed that the moulting cycle (MC) from the zoea 1 (Z 1 )-zoea 2 (Z 2 ) stage was not significantly affected by water temperature (P >0.05), remaining at approximately 3 days. However, in the Z 2 -megalopa (M) stage, the MC in the 31 degrees C group was consistently the shortest. The total developmental duration and total effective cumulative temperature during Z 1 -M in the 31 degrees C group were the lowest at 9.97 days and 250 days degrees C, respectively. According to the equation of water temperature and larval development rate, the development rate was the fastest when the water temperature was 31 degrees C. As the water temperature increased, the survival rate (SR) of larvae at various stages gradually decreased. The SR of the 27 degrees C group was consistently significantly higher than that of the 33 degrees C group (P <0.05), especially in the M stage, where the SR of the 33 degrees C group was only 2%, which was significantly lower than that of the 27 degrees C and 29 degrees C groups (P <0.05). Among the antioxidant indexes, both superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) were the lowest in the 29 degrees C group at 315.75 U/mg protein and 0.36 mmol/g protein, respectively, and both were significantly lower than those in the 33 degrees C group (P <0.05). Catalase (CAT) and glutathione peroxidase (GSH-PX) were both the lowest in the 31 degrees C group, and in this group the CAT was significantly lower than in the 33 degrees C group, and GSH-PX was significantly lower than in the 27 degrees C group (P <0.05). For malondialdehyde (MDA) content, the four groups were basically maintained at about 2.5 nmol/mg protein, and there was no significant difference (P >0.05). In terms of digestive enzyme activity, the activity of lipase (LPS) was basically maintained at 1.93 U/g protein. The other four digestive enzyme activity differences were mainly reflected in that the 31 and 33 degrees C groups maintained relatively higher levels than the 27 and 29 degrees C groups, especially the activities of alpha -amylase (AMS), and cellulase (CL) in the 33 degrees C group, which were significantly higher than those in the 27 and 29 degrees C groups ( P < 0 . 05). Comprehensive indicators indicate that a water temperature between 29 and 31 degrees C is the appropriate temperature for the development of the larvae of off-season breeding swimming crabs.

Microplastics (MPs) are a global concern regarding environmental pollution. This study evaluated the impacts of MPs with two sizes (5 mu m and 0.5 mu m) on hatching performance and microbiota of Sepiella japonica. The presence of MPs increased the hatching rate at some stages of the fertilization process and reduced the oxygen consumption rate at the gastrula stage. No size-dependent impact was observed. The 16S rRNA gene was sequenced to identify the flora. Clustering tags assessed species diversity in the samples with 97% similarity. Proteobacteria was the most abundant phylum in all three groups. MPs publicity appreciably modified flower structure. The most variable genera were Ralstonia, Methylophilus, and Pseudorhodoferax, which can furnish nutrients and modify the host's immune response. MPs exposure appeared to enrich beneficial bacteria in this study. The presence of MPs with a size of 5 mu m played a greater role in this process, which is supported by presumptive functions. However, since the adsorption of suspended MPs on aquatic eggs can have cascading effects on specific life stages of oviparous animals, regular monitoring of microbial communities is necessary after juvenile S. japonica formation to prevent disease outbreaks.

为探究横带髭鲷早期发育阶段氨基酸和脂肪酸的组成及变化规律,运用生化分析法,测定了横带髭鲷受精卵、初孵仔鱼、开口前仔鱼、后期仔鱼和稚鱼5个阶段的氨基酸和脂肪酸的种类及含量变化.结果表明:总必需氨基酸含量由受精卵到初孵仔鱼,再到开口前仔鱼显著下降,直到后期仔鱼开口摄食后显著上升,由后期仔鱼到稚鱼发育过程又显著降低(P＜0.05);必需氨基酸总含量与氨基酸总含量的比值范围在52.53％～56.47％,各阶段的必需氨基酸总含量均高于非必需氨基酸;各发育阶段的必需游离氨基酸的含量均高于非必需游离氨基酸含量,游离氨基酸与总氨基酸的比值范围为2.05％～12.76％,除开口前仔鱼和后期仔鱼差异不显著外,其他时期均差异显著(P＜0.05);各个早期发育阶段中,PUFA的含量均最高,占总脂肪酸含量的32.22％～44.52％,PUFA在发育早期表现为在受精卵阶段具有较高含量,孵化出膜后迅速降低,之后又逐渐升高;初孵仔鱼阶段的SFA、MUFA、PUFA、n-3PUFA、n-6PUFA和ΣDHA+EPA实际含量均最大,随着初孵仔鱼的生长,除了 n-6PUFA在稚鱼阶段略有升高外,其余种类脂肪酸的总含量均在不断降低.研究表明:总氨基酸、必需氨基酸及非必需氨基酸含量在受精卵阶段含量较高,这可能与自身卵黄囊储备较丰富的营养物质有关.后期仔鱼期到稚鱼期PUFA的含量显著下降,在此阶段应加强生物饵料的营养强化技术,或投喂富含高度不饱和脂肪酸的生物饵料.

探究横带髭鲷(Hapalogenys analis)的种质资源情况以及群体的遗传多样性和遗传结构,对于其增养殖实践尤为重要.微卫星分子标记在研究物种种质情况及遗传信息方面有很大优势.采用基因组survey测序方法开发横带髭鲷微卫星位点,结果表明,横带髭鲷基因组大小为543 Mb;微卫星位点丰富,共检测到280 378个完美型微卫星位点,相对丰度为415.17个/Mb.二核苷酸重复是最丰富的微卫星类型(56.05％),其次为单核苷酸(29.20％)、三核苷酸(10.28％)、四核苷酸(2.99％)、五核苷酸(1.03％)、六核苷酸(0.45％)重复,短序列重复类型占95.53％.重复单元中A/T,TG/CA为优势重复单元,分别占总微卫星位点数的22.37％和21.98％;10次重复和6次重复的微卫星位点数量最多,占横带髭鲷基因组微卫星总数的14.60％和12.46％.利用筛选出的20对多态性微卫星位点扩增一个供试群体进行群体遗传学检测.结果表明,各位点等位基因数从5到13不等,均值为8.75个;平均观测杂合度(Ho)和期望杂合度(He)分别为0.808和0.863;多态信息含量(PIC)均值为0.826,且均大于0.5.经Bonferroni校正后有5个位点显著偏离哈迪-温伯格平衡(P＜0.001);有4个位点存在无效等位基因.研究结果中的微卫星位点可用于今后横带髭鲷遗传育种和群体遗传学的研究.

横带髭鲷为近海中下层鱼,喜栖息于多岩礁的海区,是一种典型的岛礁性鱼.我国沿海均有分布,因其具营养价值较高、体表有美观条纹等优点,深受养殖者及消费者的喜爱,是一种具有较高食用价值和观赏价值的优质鱼.本文通过研究横带髭鲷的摄食习性,观察其仔鱼阶段的摄食节律,探索出一种高效的仔鱼转食配合饲料的驯食方法.该方法具有驯食周期短、驯化成活率高、畸形率低等优点,可为横带髭鲷的规模化人工繁育提供技术支持.

横带髭鲷(Hapalogenys mucronatus)隶属于鲈形目(Perciforms)、石鲈科(Pamadasyidae)、髭鲷属(Hapalogenys),俗称铜盆鱼、十六枚等.喜栖息于多岩礁的海区,是一种典型的岛礁性鱼类,在我国沿海均有分布,具有较高食用价值和观赏价值.由于野生资源总量匮乏,无明显的盛渔期,渔获量较低,市场供不应求.目前一般在繁殖季节,直接收集海钓的3龄以上性成熟亲鱼,经过暂养后进行人工催产,海钓的亲鱼往往存在被鱼钩钩伤、易患溃烂病、难以适应养殖环境等问题.传统的亲鱼培育方法不仅成活率低,即便获得少量受精卵,受精率极低,无法实现规模化人工繁育.现介绍通过收集拖虾船捕获野生2龄以下的未成熟个体,进行人工养殖到性成熟年龄的方法,经过越冬期间的亲鱼强化培育,可获得充足优质繁殖的亲鱼,提高驯养的成活率.

采用实验生态学方法研究了不同盐度梯度(10、15、20、25、30和35)和规格体重[S组(1.55±0.37)g,M 组(3.92±0.74)g,L 组(9.08±1.38)g]对横带髭鲷(Hapalogenys mucronatus)幼鱼耗氧率(Ro)和排氨率(RN)的影响,以及氧氮比(O∶N)对横带髭鲷幼鱼能源物质的分析.结果表明,当盐度恒定时,横带髭鲷幼鱼的耗氧率和排氨率均随体重(W)的增加而下降,体重与单位体重的耗氧率之间呈一元三次函数关系,体重与单位体重的排氨率之间呈幂函数关系;盐度和体重对横带髭鲷幼鱼的耗氧率、排氨率均有显著影响(P＜0.05),但盐度和体重的交互作用对耗氧率、排氨率影响均不显著(P＞0.05).随着盐度的升高,三种规格横带髭鲷幼鱼耗氧率和排氨率均呈先升高后降低的趋势,耗氧率在盐度20时出现相对最大值,而排氨率则在盐度25时出现相对最大值.三种规格横带髭鲷幼鱼O:N值均随盐度的上升呈波动趋势,O:N值波动范围在5.035～7.533之间,其总平均值为5.916;同一规格不同盐度间O:N值差异不显著(P＞0.05),而三种规格O:N平均值表现为S组(6.908)显著高于M组(5.426)和L组(5.414)(P＜0.05),L组和M组差异不显著(P＞0.05).三种规格横带髭鲷幼鱼在盐度10～35时主要以蛋白质作为主要能源物质.

横带髭鲷(Hapalogenysmucronatus)为我国东南沿海具有良好发展前景的养殖鱼类,目前亟待突破其规模化苗种培育的瓶颈技术问题.为探究横带髭鲷仔鱼发育阶段的摄食和生长特性,采用实验生态学方法,在水温(24±0.2)℃、盐度为26的条件下对饥饿仔鱼形态发育、生长、不可逆点及投喂状态下的摄食节律进行研究.结果表明,孵化出膜后的初孵仔鱼,3日龄开口摄食,进入混合营养期,3日龄卵黄囊消耗完毕,油球于8日龄消耗完全,混合营养期为5d.饥饿组仔鱼全长呈先增长后下降趋势,拐点出现在3日龄,在4日龄有畸形仔鱼出现.饥饿仔鱼初次摄食率为10.12％,最高初次摄食率出现在7日龄,为85.06％;PNR出现在7日龄和8日龄之间,至9日龄全部死亡.早期仔鱼(7日龄)的摄食高峰出现在7:00、11:00和15:00,晚期仔鱼(14日龄)在7:00、11:00、15:00和19:00四个时间段,摄食高峰均出现在白天,属于典型的白天摄食类型,随着仔鱼的生长发育,摄食高峰有所延长.横带髭鲷仔鱼最佳开口摄食时间在3日龄,掌握仔鱼的摄食高峰期,在此时间段驯化配合饲料,对于活体饵料向配合饲料的驯食转化具有重要实践意义.

Abstract The complete mitochondrial genome sequence of Omobranchus fasciolatoceps was firstly described in this article. The total length of mitogenome was 16,569 bp. It contains 13 protein-coding genes, 22 tRNA genes, and two ribosomal RNA genes. The overall base composition of H-strand was 29.04% A, 27.14% C, 27.89% T, and 15.93% G, with an A＋T bias of 56.93%. The phylogenetic analysis results showed that the O. fasciolatoceps was most closely related to O. elegans.

采用4种不同规格(平均胴长0.8、1.0、1.2、1.4 cm)曼氏无针乌贼幼体进行饵料驯化实验,比较分析了活体糠虾和冰鲜毛虾对其饵料驯化期间生长及存活的影响.通过分析2种饵料对4种规格曼氏无针乌贼幼体驯化期间胴长相对增长率、体质量相对增长率和成活率以及2种饵料间3个指标相对比值的变化趋势,结果表明曼氏无针乌贼胴长1.2 cm左右时开始驯化冰鲜毛虾,其胴长相对增长率44.44％±5.89％、体质量相对增长率121.73％±18.21％和成活率88.33％±2.89％均与胴长1.4 cm组差异不显著(P>0.05),但均显著高于胴长0.8和1.0 cm 2组(P<0.05),且其成活率与活体糠虾组差异不显著(P>0.05).曼氏无针乌贼胴长达1.2 cm左右时开始驯化冰鲜毛虾等死饵料是最佳时节.

植食性海水鱼主要以海水中的浮游植物、浮游动物、小型海藻等为食.在养殖实践中,梭鱼、鲻鱼、篮子鱼等植食性海水鱼的物质能量转化及生态优势已得到了广泛关注和利用,在与虾、肉食性鱼等种类的复合立体养殖中都取得了良好效果.斑(鰶)(Konosirus punctatus)属硬骨鱼纲、鲱形目、鲱科,在我国黄渤海、东海、南海均有分布,主要栖息在内湾浅海区,以海湾和河口居多,是我国沿海常见的小型经济鱼品种.

本文旨在对横带髭鲷(Hapaloyenys mucronatus)早期生活史阶段的生长发育特征进行观察和测量,详细描述胚胎和仔稚幼鱼各发育时期的时间和形态特征.结果 表明,横带髭鲷的受精卵为透明的圆球形浮性卵,卵径(1.32±0.01)mm,多个大小不等的淡黄色油球.胚胎发育经历6个主要阶段:卵裂前期、卵裂期、囊胚期、原肠胚期、器官形成期和出膜期.在水温(21.0±0.2)℃,盐度26条件下,受精卵约经36 h 30 min孵出初孵仔鱼.胚后发育阶段的划分主要依据卵黄囊、油球、鳍膜、鳞片和体色条带的变化,可分为早期仔鱼期、晚期仔鱼期、稚鱼期和幼鱼期4个阶段.初孵仔鱼全长(2.96±0.15) mm,具单个油球,3日龄开口摄食轮虫,4日龄卯黄囊消耗完全,9日龄油球消耗完全,24日龄鳍膜完全消失,体侧和腹部出现初生栉鳞,进入稚鱼期.45日龄被覆栉鳞,全身黑色素加深,腹部呈灰白色,进入幼鱼期.横带髭鲷早期发育过程中有3个重要形态特征:从2日龄至38日龄,横带髭鲷的头背部1～9枚硬棘出现和退化;从5日龄开始腹鳍出现并正异速生长,至38日龄腹鳍逐渐由长翅形退变为扇形;56日龄幼鱼期,体表明显可见6条横向黑色素带,在体态上与成鱼基本相同.