diff --git a/src/multi_swarm/dashboard/aquarium.py b/src/multi_swarm/dashboard/aquarium.py
new file mode 100644
index 0000000..a94ba13
--- /dev/null
+++ b/src/multi_swarm/dashboard/aquarium.py
@@ -0,0 +1,281 @@
+"""Aquarium 2D visualization helpers.
+
+Builds a list of fish records from a merged DataFrame (evaluations + genomes)
+and renders a self-contained HTML/JS canvas animation, embeddable in Streamlit
+via ``streamlit.components.v1.html``.
+"""
+
+from __future__ import annotations
+
+import json
+import math
+from typing import Any
+
+import pandas as pd  # type: ignore[import-untyped]
+
+# Color palette per cognitive style. Default fallback for unknown styles is grey.
+STYLE_COLORS: dict[str, str] = {
+    "physicist": "#4cc9f0",
+    "biologist": "#52b788",
+    "historian": "#e76f51",
+    "meteorologist": "#ffd166",
+    "ecologist": "#a78bfa",
+    "engineer": "#fb6f92",
+}
+DEFAULT_COLOR: str = "#94a3b8"
+
+
+def build_fish_dataset(merged: pd.DataFrame, max_fish: int = 30) -> list[dict[str, Any]]:
+    """Build a list of fish records from a merged evaluations+genomes DataFrame.
+
+    Expects columns: ``genome_id``, ``fitness``, ``cognitive_style``, ``n_trades``,
+    ``dsr``. Rows with NaN ``fitness`` are dropped. Result is sorted by fitness
+    descending and capped at ``max_fish`` entries.
+    """
+    if merged.empty:
+        return []
+
+    cols_needed = ["genome_id", "fitness", "cognitive_style", "n_trades", "dsr"]
+    available = [c for c in cols_needed if c in merged.columns]
+    df = merged[available].copy()
+
+    if "fitness" not in df.columns:
+        return []
+
+    df = df.dropna(subset=["fitness"])
+    df = df.sort_values("fitness", ascending=False).head(max_fish)
+
+    fish: list[dict[str, Any]] = []
+    for _, row in df.iterrows():
+        gid = str(row.get("genome_id", ""))
+        fitness_val = float(row.get("fitness", 0.0))
+        if math.isnan(fitness_val):
+            fitness_val = 0.0
+        style_raw = row.get("cognitive_style", None)
+        style = str(style_raw) if style_raw is not None and not _is_nan(style_raw) else "unknown"
+        n_trades_raw = row.get("n_trades", 0)
+        n_trades = int(n_trades_raw) if not _is_nan(n_trades_raw) else 0
+        dsr_raw = row.get("dsr", 0.0)
+        dsr = float(dsr_raw) if not _is_nan(dsr_raw) else 0.0
+        fish.append(
+            {
+                "id": gid,
+                "fitness": fitness_val,
+                "cognitive_style": style,
+                "n_trades": n_trades,
+                "dsr": dsr,
+            }
+        )
+    return fish
+
+
+def _is_nan(v: Any) -> bool:
+    try:
+        return bool(pd.isna(v))
+    except (TypeError, ValueError):
+        return False
+
+
+def build_aquarium_html(
+    fish: list[dict[str, Any]],
+    canvas_w: int = 1000,
+    canvas_h: int = 600,
+    show_labels: bool = False,
+) -> str:
+    """Build the self-contained HTML/JS string for the aquarium canvas."""
+    fish_json = json.dumps(fish)
+    palette_json = json.dumps(STYLE_COLORS)
+    default_color = DEFAULT_COLOR
+    show_labels_js = "true" if show_labels else "false"
+
+    # All braces inside <style>/<script> are escaped to literals using {{ }}
+    # so we can use Python f-string substitution for the few JSON payloads.
+    return f"""
+<div style="position:relative;width:100%;height:{canvas_h}px;">
+  <canvas id="aquarium" width="{canvas_w}" height="{canvas_h}"
+          style="width:100%;height:{canvas_h}px;border-radius:12px;
+                 background:linear-gradient(180deg,#0a2540 0%,#1a4d80 100%);
+                 display:block;"></canvas>
+</div>
+<script>
+(function() {{
+  const FISH_DATA = {fish_json};
+  const STYLE_COLORS = {palette_json};
+  const DEFAULT_COLOR = {json.dumps(default_color)};
+  const SHOW_LABELS = {show_labels_js};
+
+  const canvas = document.getElementById('aquarium');
+  if (!canvas) return;
+  const ctx = canvas.getContext('2d');
+  const W = canvas.width;
+  const H = canvas.height;
+
+  // Normalize fitness for sizing.
+  let maxFit = 0.0;
+  for (const f of FISH_DATA) {{
+    if (typeof f.fitness === 'number' && f.fitness > maxFit) maxFit = f.fitness;
+  }}
+
+  function lerp(a, b, t) {{ return a + (b - a) * t; }}
+
+  function radiusFor(fitness) {{
+    if (maxFit <= 0) return 8;
+    const t = Math.max(0.05, Math.min(1.0, fitness / maxFit));
+    return lerp(8, 40, t);
+  }}
+
+  function colorFor(style) {{
+    return STYLE_COLORS[style] || DEFAULT_COLOR;
+  }}
+
+  // Init fish state.
+  const fish = FISH_DATA.map((f, idx) => {{
+    const r = radiusFor(f.fitness);
+    return {{
+      id: f.id,
+      fitness: f.fitness,
+      style: f.cognitive_style,
+      color: colorFor(f.cognitive_style),
+      r: r,
+      x: Math.random() * (W - 2 * r) + r,
+      y: Math.random() * (H - 2 * r) + r,
+      vx: (Math.random() - 0.5) * 1.5,
+      vy: (Math.random() - 0.5) * 1.0,
+      rank: idx,
+    }};
+  }});
+
+  // Bubbles for ambience.
+  const N_BUBBLES = 25;
+  const bubbles = Array.from({{length: N_BUBBLES}}, () => ({{
+    x: Math.random() * W,
+    y: Math.random() * H,
+    r: 1 + Math.random() * 3,
+    vy: 0.3 + Math.random() * 0.7,
+  }}));
+
+  function drawBubble(b) {{
+    ctx.beginPath();
+    ctx.arc(b.x, b.y, b.r, 0, Math.PI * 2);
+    ctx.fillStyle = 'rgba(255,255,255,0.18)';
+    ctx.fill();
+  }}
+
+  function updateBubble(b) {{
+    b.y -= b.vy;
+    if (b.y < -10) {{
+      b.y = H + 5;
+      b.x = Math.random() * W;
+    }}
+  }}
+
+  function drawFish(f) {{
+    const facingLeft = f.vx < 0;
+    ctx.save();
+    ctx.translate(f.x, f.y);
+    if (facingLeft) ctx.scale(-1, 1);
+
+    // Halo for top-3 fish.
+    if (f.rank < 3) {{
+      const grad = ctx.createRadialGradient(0, 0, f.r * 0.5, 0, 0, f.r * 2.0);
+      grad.addColorStop(0, f.color + 'aa');
+      grad.addColorStop(1, f.color + '00');
+      ctx.fillStyle = grad;
+      ctx.beginPath();
+      ctx.arc(0, 0, f.r * 2.0, 0, Math.PI * 2);
+      ctx.fill();
+    }}
+
+    // Body (ellipse).
+    ctx.fillStyle = f.color;
+    ctx.beginPath();
+    ctx.ellipse(0, 0, f.r, f.r * 0.6, 0, 0, Math.PI * 2);
+    ctx.fill();
+
+    // Tail (triangle pointing left, body extends right).
+    ctx.beginPath();
+    ctx.moveTo(-f.r, 0);
+    ctx.lineTo(-f.r * 1.6, -f.r * 0.5);
+    ctx.lineTo(-f.r * 1.6, f.r * 0.5);
+    ctx.closePath();
+    ctx.fill();
+
+    // Eye.
+    ctx.fillStyle = '#ffffff';
+    ctx.beginPath();
+    ctx.arc(f.r * 0.45, -f.r * 0.15, Math.max(1.5, f.r * 0.12), 0, Math.PI * 2);
+    ctx.fill();
+    ctx.fillStyle = '#1a1a1a';
+    ctx.beginPath();
+    ctx.arc(f.r * 0.50, -f.r * 0.15, Math.max(0.8, f.r * 0.06), 0, Math.PI * 2);
+    ctx.fill();
+
+    ctx.restore();
+
+    if (SHOW_LABELS && f.id) {{
+      ctx.fillStyle = 'rgba(255,255,255,0.85)';
+      ctx.font = '10px sans-serif';
+      ctx.textAlign = 'center';
+      ctx.fillText(String(f.id).slice(0, 6), f.x, f.y - f.r - 4);
+    }}
+  }}
+
+  function updateFish(f) {{
+    // Random perturbation (organic motion).
+    f.vx += (Math.random() - 0.5) * 0.05;
+    f.vy += (Math.random() - 0.5) * 0.05;
+
+    // Clamp speed.
+    const speed = Math.hypot(f.vx, f.vy);
+    const maxSpeed = 1.5;
+    if (speed > maxSpeed) {{
+      f.vx = (f.vx / speed) * maxSpeed;
+      f.vy = (f.vy / speed) * maxSpeed;
+    }}
+
+    f.x += f.vx;
+    f.y += f.vy;
+
+    // Bounce on edges.
+    if (f.x < f.r) {{ f.x = f.r; f.vx = -f.vx; }}
+    if (f.x > W - f.r) {{ f.x = W - f.r; f.vx = -f.vx; }}
+    if (f.y < f.r) {{ f.y = f.r; f.vy = -f.vy; }}
+    if (f.y > H - f.r) {{ f.y = H - f.r; f.vy = -f.vy; }}
+  }}
+
+  function frame() {{
+    ctx.clearRect(0, 0, W, H);
+
+    // Subtle current lines.
+    ctx.strokeStyle = 'rgba(255,255,255,0.04)';
+    ctx.lineWidth = 1;
+    for (let i = 0; i < 6; i++) {{
+      const y = (H / 6) * i + (Date.now() / 50 % (H / 6));
+      ctx.beginPath();
+      ctx.moveTo(0, y);
+      ctx.lineTo(W, y);
+      ctx.stroke();
+    }}
+
+    for (const b of bubbles) {{
+      updateBubble(b);
+      drawBubble(b);
+    }}
+    for (const f of fish) {{
+      updateFish(f);
+      drawFish(f);
+    }}
+    requestAnimationFrame(frame);
+  }}
+
+  if (fish.length === 0) {{
+    ctx.fillStyle = 'rgba(255,255,255,0.7)';
+    ctx.font = '16px sans-serif';
+    ctx.textAlign = 'center';
+    ctx.fillText('Acquario vuoto: nessun genoma da mostrare.', W / 2, H / 2);
+  }} else {{
+    requestAnimationFrame(frame);
+  }}
+}})();
+</script>
+"""
diff --git a/src/multi_swarm/dashboard/pages/04_aquarium.py b/src/multi_swarm/dashboard/pages/04_aquarium.py
new file mode 100644
index 0000000..a52ac94
--- /dev/null
+++ b/src/multi_swarm/dashboard/pages/04_aquarium.py
@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+import streamlit as st
+import streamlit.components.v1 as components
+
+from multi_swarm.dashboard.aquarium import (
+    STYLE_COLORS,
+    build_aquarium_html,
+    build_fish_dataset,
+)
+from multi_swarm.dashboard.data import (
+    evaluations_df,
+    generations_df,
+    genomes_df,
+    get_repo,
+    list_runs_df,
+)
+
+st.title("Aquarium 2D")
+st.caption(
+    "Ogni genoma è un pesce: dimensione proporzionale alla fitness, "
+    "colore per cognitive_style."
+)
+
+db_path = st.session_state.get("db_path", "./runs.db")
+repo = get_repo(db_path)
+
+runs = list_runs_df(repo)
+if runs.empty:
+    st.info("Nessuna run.")
+    st.stop()
+
+selected = st.selectbox("Run", runs["id"].tolist())
+
+gens = generations_df(repo, selected)
+gen_options: list[int | None] = [None]
+if not gens.empty:
+    gen_options.extend(sorted(gens["generation_idx"].unique().tolist()))
+
+def _fmt_gen(v: int | None) -> str:
+    return "tutte le generazioni" if v is None else f"gen {v}"
+
+# Default to latest gen if available.
+default_idx = len(gen_options) - 1 if len(gen_options) > 1 else 0
+gen_choice = st.selectbox(
+    "Generazione", gen_options, index=default_idx, format_func=_fmt_gen
+)
+
+with st.sidebar:
+    st.subheader("Aquarium controls")
+    max_fish = st.slider("Max pesci", min_value=5, max_value=100, value=30, step=1)
+    show_labels = st.toggle("Mostra ID genoma", value=False)
+    if st.button("Refresh"):
+        st.rerun()
+
+evals = evaluations_df(repo, selected)
+genomes = genomes_df(repo, selected, generation_idx=gen_choice)
+
+if evals.empty or genomes.empty:
+    st.warning("Nessun dato disponibile per questa run/generazione.")
+    st.stop()
+
+merged = evals.merge(
+    genomes, left_on="genome_id", right_on="id", how="inner", suffixes=("", "_g")
+)
+if merged.empty:
+    st.warning("Nessuna evaluation associata ai genomi della generazione scelta.")
+    st.stop()
+
+fish = build_fish_dataset(merged, max_fish=max_fish)
+st.write(f"Visualizzati {len(fish)} pesci (top per fitness).")
+
+html_str = build_aquarium_html(
+    fish, canvas_w=1000, canvas_h=600, show_labels=show_labels
+)
+components.html(html_str, height=620, scrolling=False)
+
+with st.expander("Legenda colori"):
+    legend_md = "\n".join(
+        f"- <span style='color:{color};font-weight:bold;'>&#9679;</span> "
+        f"`{style}`"
+        for style, color in STYLE_COLORS.items()
+    )
+    st.markdown(legend_md, unsafe_allow_html=True)
diff --git a/src/multi_swarm/dashboard/streamlit_app.py b/src/multi_swarm/dashboard/streamlit_app.py
index 1ddfff4..2538167 100644
--- a/src/multi_swarm/dashboard/streamlit_app.py
+++ b/src/multi_swarm/dashboard/streamlit_app.py
@@ -13,6 +13,7 @@ Naviga le pagine nel menu a sinistra:
 - **Overview**: ultima run e stato globale.
 - **GA Convergence**: fitness per generazione.
 - **Genomes**: top-K genomi e ispezione qualitativa.
+- **Aquarium**: visualizzazione 2D dei genomi come pesci animati.
 """
 )
 
diff --git a/tests/integration/test_streamlit_smoke.py b/tests/integration/test_streamlit_smoke.py
index d3425e5..475fa7b 100644
--- a/tests/integration/test_streamlit_smoke.py
+++ b/tests/integration/test_streamlit_smoke.py
@@ -1,5 +1,7 @@
 import importlib
 
+import pandas as pd
+
 
 def test_streamlit_app_imports():
     importlib.import_module("multi_swarm.dashboard.data")
@@ -12,3 +14,74 @@ def test_dashboard_data_helpers_signatures():
     assert hasattr(data, "generations_df")
     assert hasattr(data, "evaluations_df")
     assert hasattr(data, "genomes_df")
+
+
+def test_aquarium_helper_builds_html():
+    from multi_swarm.dashboard.aquarium import build_aquarium_html
+
+    fish = [
+        {
+            "id": "abc123",
+            "fitness": 0.8,
+            "cognitive_style": "physicist",
+            "n_trades": 30,
+            "dsr": 0.7,
+        },
+        {
+            "id": "def456",
+            "fitness": 0.0,
+            "cognitive_style": "biologist",
+            "n_trades": 0,
+            "dsr": 0.0,
+        },
+    ]
+    html = build_aquarium_html(fish, canvas_w=800, canvas_h=400, show_labels=True)
+    assert "canvas" in html
+    assert "abc123" in html
+    assert "physicist" in html or "4cc9f0" in html
+    assert "requestAnimationFrame" in html
+
+
+def test_aquarium_build_fish_dataset_sorts_and_caps():
+    from multi_swarm.dashboard.aquarium import build_fish_dataset
+
+    df = pd.DataFrame(
+        [
+            {"genome_id": "low", "fitness": 0.1, "cognitive_style": "physicist",
+             "n_trades": 1, "dsr": 0.0},
+            {"genome_id": "high", "fitness": 0.9, "cognitive_style": "biologist",
+             "n_trades": 10, "dsr": 0.5},
+            {"genome_id": "mid", "fitness": 0.5, "cognitive_style": "engineer",
+             "n_trades": 5, "dsr": 0.2},
+        ]
+    )
+    out = build_fish_dataset(df, max_fish=2)
+    assert len(out) == 2
+    assert out[0]["id"] == "high"
+    assert out[1]["id"] == "mid"
+    assert out[0]["cognitive_style"] == "biologist"
+
+
+def test_aquarium_build_fish_dataset_drops_nan_fitness():
+    from multi_swarm.dashboard.aquarium import build_fish_dataset
+
+    df = pd.DataFrame(
+        [
+            {"genome_id": "ok", "fitness": 0.4, "cognitive_style": "historian",
+             "n_trades": 2, "dsr": 0.1},
+            {"genome_id": "bad", "fitness": float("nan"), "cognitive_style": "ecologist",
+             "n_trades": 0, "dsr": 0.0},
+        ]
+    )
+    out = build_fish_dataset(df)
+    assert len(out) == 1
+    assert out[0]["id"] == "ok"
+
+
+def test_aquarium_empty_input_returns_empty():
+    from multi_swarm.dashboard.aquarium import build_aquarium_html, build_fish_dataset
+
+    assert build_fish_dataset(pd.DataFrame()) == []
+    html = build_aquarium_html([], canvas_w=400, canvas_h=200)
+    assert "canvas" in html
+    assert "Acquario vuoto" in html