PRACTICALNO# 1 Collection, Identification and Preservation of Fishes
Objective: To collect fish specimens from a water body, identify those using morphological
features, and preserve them for further study or reference.
Materials Required:
Fish nets (cast net, drag net, hand net)
Buckets or containers
Labels and waterproof marker
Measuring scale or caliper
Field notebook
Digital camera or phone (for documentation)
10% formalin or 70% ethanol (for preservation)
Dissecting kit (optional)
GPS device or mobile with GPS
Gloves and safety gear
COLLECTION OF FISHES
A. Selection of Site:
Choose a freshwater (river, lake, pond) or marine site based on study objectives.
Note the environmental parameters (temperature, pH, salinity, etc.)
B. Methods of Collection:
Cast Net: Thrown by hand, ideal for shallow waters.
Drag Net/Seine Net: Pulled through water, used in ponds/lakes.
Hand Picking: Small fishes from puddles or shallow streams.
Traps/Baited Hooks: For specific or elusive species.
�Record: Date, time, location (with GPS), water type, and method used.
IDENTIFICATION OF FISHES
A. Morphological Features to Observe:
Body shape and size
Fin types and positions (dorsal, pectoral, pelvic, anal, caudal)
Scales (type and pattern)
Coloration (live and after preservation)
Mouth type and position
Lateral line system
Barbels (if any)
B. Tools for Identification:
Fish identification keys or field guides
Regional fish fauna books
Online databases (e.g., FishBase: www.fishbase.org)
Tip: Take clear photos of live fish from top and sides before preservation.
3PRESERVATION OF FISHES
A. Short-term (field):
Keep live fish in aerated buckets or tubs for a few hours
If immediate preservation is needed, euthanize humanely (e.g., with clove oil solution)
B. Long-term (lab):
1. Fixation:
Use 10% formalin for initial fixation (1 part formalin + 9 parts water).
Make a small incision on the abdomen to ensure internal fixation for larger fish.
2. Storage:
After 7–10 days in formalin, transfer to 70% ethanol for long-term storage.
Store in labeled glass jars or plastic containers.
3. Labeling:
Include:
Species name (if identified)
Date and location of collection
Collector’s name
Habitat type
PRECAUTIONS:
Handle chemicals (formalin, ethanol) with care — use gloves and goggles. Avoid over-
crowding fish in holding buckets. Ensure accurate and legible labeling. Follow ethical
guidelines and local wildlife regulations.