Fish Store Break-Even Analysis: Month 13 Aquarium Retail Plan

Fixed costs $19.4K/mo Base monthly burn

Contribution margin 81% After variable costs

Break-even revenue $24.0K/mo Monthly target

Break-even timing Month 13 Cash turns flat

Break-even calculator

Test monthly revenue, variable costs, and fixed overhead against break-even for a fish store.

Lean Base Full

Monthly revenue Revenue is the pool that covers direct costs and then fixed overhead. $ Low sales High sales Variable expenses Use direct costs that rise with sales, like wholesale fish, supplies, fees, and ads. $ Low costs High costs

Money available to cover fixed costs $32,300 $39,400 revenue - $7,100 variable expenses

Margin ratio

82%

Covers fixed costs

Yes

Fixed monthly costs This is the monthly cost base the store has to cover. $ Light overhead Heavy overhead

Break-even chart Revenue Total costs

Which fish store expenses stay fixed, and which move with sales?

Cost classification

Break-even gets unreliable when fixed overhead, payroll steps, and sales-linked expenses are blended together. Treat rent as fixed, inventory as variable, and tank-load staffing as semi-fixed so Month 13 break-even is tested cleanly.

Expense	Cost	Break-Even Treatment	Common Mistake
Rent Retail Space	Fixed	Model $4,000 per month from Month 1 through Month 60.	Tying rent to sales instead of store capacity.
Store Manager Payroll	Semi-fixed	Use $5,000 per month at 1.0 FTE unless management capacity changes.	Treating every labor dollar as variable.
Animal Care Specialist Payroll	Semi-fixed	Use $3,750 per month at 1.0 FTE, then step up when tank load requires 1.5 FTE.	Missing the staffing jump as live inventory grows.
Electricity Water Utilities	Semi-variable	Start with the $1,500 monthly base, then stress-test higher water and electric use.	Ignoring filtration, heating, and water-change load.
Insurance, POS Subscription, Internet Phone, Maintenance, Security	Fixed	Model the $580 total monthly run-rate as fixed overhead.	Spreading small fixed bills across units sold.
Wholesale Live Animals Aquariums	Variable	Apply 11.5% of revenue in the first year, declining to 9.5% by the fifth year.	Hiding livestock shrink or freight pressure inside fixed overhead.
Wholesale Supplies	Variable	Apply 4.5% of revenue in the first year, declining to 3.5% by the fifth year.	Modeling supplies as a flat monthly spend.
Marketing Advertising and Payment Processing Fees	Variable	Apply 3.0% of revenue in the first year, then adjust with the forecast percentages.	Leaving sales-linked fees out of contribution margin.

How does break-even shift across lean, base, and full fish store setups?

Scenario table

Break-even shifts with traffic, conversion, and staffing, while fixed costs move more slowly. The full case gives the biggest cushion, but the lean case still clears break-even if sales hold.

Scenario figures are planning assumptions, not guaranteed results.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean store setup	$374K	$71K	$194K	81.0%	$109K	Clears break-even, but the cushion is modest.
Base store setup	$538K	$97K	$209K	81.9%	$232K	Stronger traffic keeps break-even risk low.
Full store setup	$1.07M	$183K	$223K	82.9%	$661K	Offers the widest cushion if the mix holds.

What breaks the fish store break-even plan?

Stress test

The plan still has room, but soft weekday traffic and higher livestock loss can shrink it fast. A 20% sales drop plus a $2K fixed-cost bump leaves only about $17K of cushion.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change from the base case.	$240,000	$134,000 cushion	Solid cushion, but only while traffic and loss stay stable.
Revenue shortfall	Monthly sales fall 10% to about $336,000.	$240,000	$96,000 cushion	Weekday traffic weakness trims the cushion fast.
Fixed-cost pressure	Fixed costs rise by $2,000 a month.	$264,000	$110,000 cushion	Payroll or utility creep eats break-even room fast.
Margin pressure	Variable expenses rise 5 percentage points from livestock loss and freight.	$255,000	$119,000 cushion	Higher loss and freight lower each sale's payback.
Combined pressure	Sales fall 20%, variable expenses rise 5 points, and fixed costs add $2,000.	$282,000	$17,000 cushion	That mix leaves very little room for error.

Can this fish store clear break-even before you sign the lease and buy the tanks?

Founder checklist

Sign only if the store can carry the $5.5K monthly rent-and-utility base, the tank system fits the setup budget, and cash stays alive through Month 14. The model does not feel safe until traffic, staffing, and supplier flow all hold together.

1Demand Proof390/week

Verify weekday and weekend traffic adds up to the model's 390 weekly visitors, with 180 coming on Saturday and Sunday, before you commit to the opening plan.

2Lease Load$5.5K/mo

Check that $4,000 rent plus $1,500 utilities still fits your base load before build-out, because tanks and water use raise the fixed bill fast.

3Life Support$33K

Price display aquariums, filtration, and quarantine space against the $25K and $8K budgets, and confirm live-animal suppliers can stock from Month 1 so losses and outages do not eat margin.

4Margin Mix81% CM

Test whether Year 1 pricing and the 30% live fish and 30% aquariums mix still leave about 81% contribution margin, since break-even slips if discounts or loss rates creep up.

5Staff Load4 FTE

Validate the opening team against the four-FTE Year 1 plan and the $13.3K monthly payroll base, then add hours only when weekend demand stays strong.

6RunwayMonth 14

Do not fund the $129K capex plan unless you can carry cash to the model's Month 14 low point, because the business needs room for build-out before breakeven lands in Month 13.