One folder for the whole corydoras shoal
One folder for the whole corydoras shoal matches how these catfish actually live and are bought: in groups, often added in twos and threes over time. Label the folder with the tank name and keep a front summary page showing the current number of corydoras, when each group arrived and the substrate they live on. That front page prevents the commonest filing failure with shoaling fish, where receipts exist but nobody can reconstruct how many fish the tank holds. Update the summary whenever a group is added, and date every version.
What belongs in each corydoras section
What belongs in a corydoras folder divides into purchase, tank, equipment, water and daily care sections. Purchase holds a dated record for each group bought, with the species name as sold and the number added. Tank holds substrate details, because corydoras rest and feed on the bottom and a change from sand to gravel is a significant event in their file. Equipment holds filter and heater receipts, water holds test sheets in order, and daily care holds the sinking-food routine plus behaviour notes. File substrate changes in the tank section with a date, not as a passing remark in a water sheet.
Behaviour notes that belong in the file
Behaviour notes belong in a corydoras file because the shoal's habits are the baseline every helper needs. File a dated description of normal life: where the group rests during the day, how eagerly they gather over a sinking wafer, and how often surface trips occur in a calm evening. Add new dated pages when the pattern changes, when barbels look worn, or when a new group takes time to join the established shoal. Keeping those pages in the daily care section, rather than loose in the folder, means anyone investigating a quiet week reads the baseline and the change together.
Feeding paperwork for bottom feeders
Feeding paperwork for corydoras should state exactly which sinking foods are in use, how much is offered, and when it is given. File that routine where a sitter will find it first, and include the practical warning that food must reach the substrate rather than being taken entirely at the surface by faster fish. Record changes of wafer or pellet and the shoal's response on dated lines in the same section. If frozen or live foods are part of the rotation, file their place in the week too, so a covering helper reproduces the pattern instead of improvising a richer or poorer menu.
Making the shoal's file survive real life
Making a corydoras file survive real life means giving it a digital twin and a fixed home. Keep the paper folder beside the tank's food and test kit, scan the front summary, equipment page and current routine, and store the scans with the shoal's other records. When equipment is replaced, file the new receipt in front of the old one and mark the old page as superseded rather than removing it, because warranty and maintenance questions reach backward. Arranging those copies in KinsLe under Pet Passport keeps the corydoras shoal's history portable for a vet visit, a house move or a change of keeper.