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Info

The Blue Bloon is the second weakest bloon in Bloons TD 6. It has two layers: popping it once releases a single Red Bloon, so its RBE is 2 and a leaked Blue costs 2 lives. An attack that deals 2 or more damage pops both layers in one hit.

Blues move at 1.4x the speed of a Red, a small step up that you rarely notice in practice. They have no immunities, so every damage type works on them. Like Reds, they are protected only by variant properties and by the freeze effect, which blocks sharp damage while the bloon is frozen.

Where you meet them. Blues first appear on Round 3 (5 Blues with 25 Reds), which is also the first round on Hard. Rounds 4 and 5 add 18 and 27 Blues. Round 10 is the first real spike: 102 Blues in one wave, which tests whether your opening towers have enough pierce. Round 13 follows with 50 Blues and 23 Greens, and Round 27 includes 60 Blues in its big swarm. After that, Blues mostly appear as children of Greens and of every higher bloon.

Variants

  • Camo Blue: first appears as a child of the Camo Green on Round 24. It is invisible to towers without camo detection.
  • Regrow Blue: in standard rounds you only see these when a Regrow Yellow (from Round 17) is popped down. Left alive, it regains lost layers every 3 seconds.
  • Fortified: does not apply to Blues.

Alternate Bloons Rounds. Blues are much more prominent in Alternate Bloons Rounds. Round 3 already includes 5 Regrow Blues, Round 5 has 15 Regrow Blues, and Round 7 sends 15 Camo Blues alongside 10 Regrow Blues and 2 Black Bloons. That means camo detection and some regrow control are needed long before they matter in standard play.

How to pop Blue Bloon

Every tower in the game can pop a Blue Bloon. It has no immunities and only two layers, so the goal is simply to have enough pierce and coverage to pop large groups before they reach the exit.

Which damage types work

All damage types pop Blues. The only cases where a tower fails are:

  • Camo Blues, which towers without camo detection cannot target or damage.
  • Frozen Blues, which sharp attacks cannot hit until the ice thaws.

An attack with 2 or more damage pops a Blue and its Red child in one hit. Sniper Monkeys start at 2 damage, the Wizard Monkey's 2-0-0 Arcane Blast raises its bolts to 2 damage, and the Dart Monkey's 0-0-3 Crossbow fires 3-damage bolts. For plain Blue waves this does not matter much, but multi-layer damage makes later rounds with Greens and Yellows far easier.

Early game answers

  • Dart Monkey: each dart pops 2 bloons (3 with Extra Dart Pops). Two well-placed Dart Monkeys cover the opening rounds on most maps.
  • Tack Shooter: short range but 8 tacks per volley, very good on tight bends where Blues bunch up.
  • Boomerang Monkey: its boomerangs pop several bloons on the way out and on the way back, which suits long straights.
  • Your hero: most heroes handle the first Blue rounds alone, and every pop speeds up their levelling.

Round 10: the first pierce check

Round 10 sends 102 Blues and nothing else. A single basic Dart Monkey can keep up with Rounds 3 to 9, then suddenly leaks on Round 10 because the Blues come in a dense stream. Fixes:

  1. Add a second attacking tower before Round 10 rather than upgrading the first one for range.
  2. Place towers where the track passes them twice, so each tower gets two chances at the same Blue.
  3. A Tack Shooter on a corner is one of the cheapest ways to stop dense Blue streams.

On Hard you still play Round 10. On CHIMPS and Impoppable the game starts at Round 6, so Round 10 comes only four rounds in and with very little cash, which makes it one of the first rounds where weak openings leak.

Mid and late game

From the mid game onward you rarely see Blues on their own. They come out of Greens and higher bloons, so your concern becomes cleanup: the Blues and Reds that survive after your main damage towers have spent their pierce on bigger layers. Useful cleanup towers are a Spike Factory near the exit, a 0-3-0 Blade Shooter, a 3-0-x Glaive Ricochet Boomerang or a Sniper with x-2-x Shrapnel Shot.

Hero picks

Quincy is a natural Blue popper: his arrows bounce between bloons and he gains camo detection at level 5. Obyn Greenfoot's wolf spirit deals 2 damage from level 1, enough to pop a Blue outright. Gwendolin's flames hit groups and help in the early game as well.

Knowledge and powers

  • Extra Dart Pops adds a third pop to every basic dart.
  • Road Spikes pop up to 20 bloons per pile, a cheap save if Round 10 or 13 is about to leak.
  • Camo Trap removes camo from the first 500 Camo bloons that cross it.

None of these work in CHIMPS, where Monkey Knowledge and Powers are disabled.

Rounds where Blues cause leaks

  • Round 10: 102 Blues in one dense stream. The classic early pierce check.
  • Round 13: 50 Blues and 23 Greens. More layers per bloon than Round 10.
  • Round 24: 20 Blues plus one Camo Green. The normal Blues are easy, but the Camo Green turns into a Camo Blue and a Camo Red that walk past any defense without camo detection.
  • Round 27: 60 Blues inside a 250-bloon swarm. Pierce matters more than damage.

Mode notes

  • Alternate Bloons Rounds: Round 3 brings Regrow Blues, Round 5 brings 15 more, and Round 7 sends 15 Camo Blues. If you rely on a single Dart Monkey, you will leak in the first few rounds. Get camo detection early (a base Ninja Monkey, a 0-0-2 Dart Monkey or a hero with camo detection) and enough pierce to stop Regrows from rebuilding.
  • CHIMPS: one life and no knowledge. Make sure your opening has both pierce and range before Round 10.

Common mistakes

  1. Spending early cash on range upgrades for a single tower instead of adding a second tower before Round 10.
  2. Placing towers only at the start of the track, so nothing catches the Blues that slip through.
  3. Ignoring camo until the Round 24 Camo Green walks through.
  4. Freezing Blues with an Ice Monkey right in front of Dart Monkeys that cannot pop frozen bloons.

Frequently asked questions

What round do Blue Bloons first appear in BTD6?

Round 3, with 5 Blues and 25 Reds. In Alternate Bloons Rounds they can appear as early as Round 1 when you start earlier than Hard allows.

What is inside a Blue Bloon?

One Red Bloon. That gives it an RBE of 2, and leaking one costs 2 lives.

How do I beat Round 10 in BTD6?

Round 10 is 102 Blues. Have at least two attacking towers or a Tack Shooter on a corner before it starts, and place them where the track passes them more than once.

Are Blue Bloons faster than Red Bloons?

Yes. Blues move at 1.4x the speed of a Red.

Can Blue Bloons be camo or regrow?

Yes. Camo Blues come from the Camo Green on Round 24, and Regrow Blues appear when Regrow Yellows are popped down from Round 17 onward. Alternate Bloons Rounds sends both much earlier.