Goldfish Mode for Commander Decks
Most online goldfish testers get the basics right: shuffle, draw seven, maybe click through a few turns. But they fall apart the moment your deck does anything interesting with mana.
Play a Sol Ring on turn one? The tester doesn’t track that you now have three mana on turn two. Deploy a Llanowar Elves? It sits there doing nothing because the simulator doesn’t understand summoning sickness. And forget about running enough tests to actually learn something—you’re stuck drawing one hand at a time, hoping your sample of three tells you anything useful.
Icarian’s goldfish mode fixes this.
How It Works
Start a goldfish session from any deck. You’ll draw seven cards, see your commander waiting in the command zone, and decide whether to keep or mulligan.
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We use the London mulligan rule: draw seven, then put cards on bottom equal to how many times you’ve mulliganed. The simulator automatically puts your highest-CMC cards on bottom—the same heuristic most players use in real games.
Click “Next Turn” to advance. Each turn, the simulator:
- Draws a card
- Plays a land (if you have one)
- Plays a mana dork (cheapest castable, with proper summoning sickness)
- Plays a mana rock (cheapest castable)
This mirrors realistic goldfish behavior. You’re not making strategic decisions—you’re testing whether your deck can function.
Mana Tracking That Actually Works
The part that matters: we track your mana correctly.
Mana dorks can’t tap the turn they enter. Mana rocks that enter tapped (like Worn Powerstone) don’t produce mana immediately. Sol Ring produces two. The simulator knows all of this.
Your total available mana updates each turn, accounting for:
- Lands in play
- Mana dorks (minus summoning sickness)
- Mana rocks (with correct production amounts)
When you have enough mana—and the right colors—to cast your commander, the session records which turn that happened. This is the number you actually care about.
Commander Availability
Speaking of commanders: the simulator tracks when you can first cast yours.
It’s not just “do I have five mana for my five-drop commander.” It checks color requirements too. If your commander costs 2WU, you need two sources that produce white and blue, not just four lands.
After several sessions, you’ll know your deck’s realistic commander timing. Turn 4 consistently? Your ramp is solid. Turn 7? You might need more acceleration.
Batch Simulation
Here’s where it gets useful: run 10 simulations at once.
One opening hand tells you almost nothing. Ten hands start to show patterns. Are you mulliganing 40% of the time? That’s a problem. Is your commander consistently available by turn 5? That’s the goal.
The session history tracks every run. You can see trends over time—especially useful after making deck changes. Cut two lands and add ramp? Run another batch and compare.
What It Won’t Do
Goldfish testing has limits. There’s no opponent, no interaction, no combat math. You’re testing your deck’s engine in isolation.
Use goldfish mode for:
- Mana curve evaluation
- Land count tuning
- Ramp package testing
- Commander timing
Use real games for everything else.
Whats next?
Right now we don’t account for cost reducers (e.g. Emerald Medallion) or rituals. We will continue to improve this with the goal being to help you understand how your deck ramps and when you can realistically get your commander out.
Goldfish mode is available now for all of your decks. Open any deck you own and click “Test Deck” to start your first session.