Why a shrimp tank needs a stricter record than other tanks
Copper is the quiet enemy in a shrimp tank: it is harmless to most fish at the levels found in common products, but it is toxic to shrimp and other invertebrates, and it can arrive through completely ordinary purchases. Some fertilisers include copper as a trace element. Some plant treatments and algae products are copper-based. Plants themselves can carry residues from treatments used by the grower or the shop to keep them snail-free. Because a shrimp tank can be poisoned by a product that was perfectly safe in your fish tank downstairs, memory is not a reliable gatekeeper — a written record of everything that has gone in is.
Keep an approved-inputs list, not just a diary
Frame the record as a closed list rather than a journal. Every fertiliser you use gets an entry before its first use: the full product name, the date you checked its ingredients, and what the label said about copper. Every plant gets an entry when it goes in: species, source, and how it was prepared — rinsed, soaked, quarantined in a bucket for some days, or planted straight in. Then the rule that makes the list work: nothing enters the water unless it appears on the list first. A diary records what happened; a closed list decides what may happen, and for a copper-free tank the second is the one that protects the colony.
Reading labels for copper in its various disguises
The check itself needs care, because ingredient lists do not always shout. Look for copper named plainly, and for its compound forms in trace-element lists — if a fertiliser's ingredients mention copper in any wording, it does not go on the approved list for this tank, however small the amount, because shrimp keepers have no reliable home way to judge a safe level and the colony is not worth the experiment. Note the outcome on the record either way, including products you rejected and why: a rejected-products note stops you re-checking the same bottle in the shop every few months, and stops anyone helping you from helpfully buying it.
Plants are the gap in most records
Fertilisers get checked because they come with ingredient lists; plants slip in on trust. Yet a plant grown in a nursery system treated against snails, or held in a shop tank that was treated, can carry enough residue to harm a colony — which is why the plant entries matter as much as the fertiliser ones. Log the preparation honestly: a rinse under the tap is not the same as several days soaking in clean water with changes, and if shrimp losses ever follow a planting, the record is what lets you work out which introduction differed. Tissue-culture plants, grown sealed in cups, are worth a note in the record too, as they arrive without tank treatments behind them.
The record also protects the tank from other people
Shrimp tanks often receive gifts — a cutting from a friend's tank, a fertiliser sample at a show — and help from family members who dose what they find beside the tank. The approved list handles both kindly: the cutting is logged with its source and preparation like any purchase, and the helper doses only what the list approves. Kept in a KinsLe Pet Passport with the tank's water-test log, the approved-inputs record also gives you the evidence trail if the colony ever does crash — what went in, from where, and when — instead of a room full of suspects and no way to tell them apart.