Neosho County State Fishing Lake algae bloom history
The Kansas Department of Health and Environment has tested Neosho County State Fishing Lake 7 times since 2019, usually after someone reported a possible bloom. 6 samples (86%) reached at least Watch level, and 5 reached Warning level or higher.
- 2019 3 samples, Warning
- 2020 None
- 2021 4 samples, Warning
When do algae blooms happen at Neosho County State Fishing Lake?
At Neosho County State Fishing Lake, reports are most often logged in August, September and October.
Reports are spread across the year, with 67% between May and September.
Blooms can appear, move with the wind and fade within hours or days, so the time of year is only a guide.
Recent Neosho County State Fishing Lake algae reports
| Date | Location | Result |
|---|---|---|
| 25 October 2021 | Neosho County Sfl | Warning level · microcystin 1.4 µg/L, 409,384 cyanobacteria cells/mL |
| 11 October 2021 | Neosho County Sfl | Warning level · microcystin 0.56 µg/L, 262,832 cyanobacteria cells/mL |
| 20 September 2021 | Neosho County Sfl | Warning level · microcystin 1.1 µg/L, 608,695 cyanobacteria cells/mL |
| 9 August 2021 | Neosho County Sfl | Warning level · microcystin 1.9 µg/L, 373,118 cyanobacteria cells/mL |
| 7 October 2019 | Neosho County Sfl | Below advisory levels · microcystin not detected, 60,177 cyanobacteria cells/mL |
| 9 September 2019 | Neosho County Sfl | Watch level · microcystin 1 µg/L, 168,551 cyanobacteria cells/mL |
| 19 August 2019 | Neosho County Sfl | Warning level · microcystin 2.5 µg/L, 500,857 cyanobacteria cells/mL |
What the Kansas results mean
KDHE sets each advisory from lab results or what staff see at the lake. Samples on this page are labelled with the level their results reached.
- Watch
- A bloom is visible, microcystin is above 4 µg/L, or there are more than 80,000 cyanobacteria cells per mL. Avoid algae and keep people and pets from swimming near it or drinking the water.
- Warning
- Microcystin above 8 µg/L, more than 250,000 cells per mL, or heavy surface scum. Avoid all contact with the water, including fishing and boating.
- Hazard
- Microcystin above 2,000 µg/L or more than 10 million cells per mL. KDHE recommends closing all or part of the lake and sometimes the shore nearby.
Is Neosho County State Fishing Lake safe for dogs?
Dogs are at the greatest risk from toxic algae. They swallow water while swimming, eat scum on the shore and lick algae off their fur afterwards, and a small amount can kill a dog within hours.
- Keep your dog on a lead near water that looks green, scummy, foamy or discoloured, and away from algae washed up on the shore.
- If your dog gets in, rinse it straight away with clean water and don't let it lick its coat.
- Call a vet immediately if your dog vomits, drools, has diarrhoea, staggers, shakes or seems weak after being near the water.
Read the full guide to toxic algae and dogs: symptoms, what to do in the first minutes and how vets treat it.
Health effects of toxic algae
Blue-green algae (cyanobacteria) can produce toxins that affect the liver, nervous system and skin. Swallowing water during a bloom can cause stomach pain, vomiting and diarrhoea. Skin contact can cause rashes, and breathing spray from the water can irritate the eyes, nose and throat. Children are at higher risk because they are smaller and more likely to swallow water.
How to spot a bloom
Toxic blooms can look like pea soup, spilled paint or green streaks on the surface, and they can also be blue, brown, white or red. Scum often collects along the shore downwind. If you can't see your feet in knee-deep water, or you aren't sure, stay out.
Don't drink untreated lake water, and don't boil it to make it safe: boiling doesn't destroy algal toxins. If you feel unwell after contact with the water, contact a doctor or Poison Control on 1-800-222-1222.
Nearby lakes with algae reports
- Parsons Lake13 km away, 28 reports, last in 2026
- Thayer Old City Lake27 km away, 3 reports, last in 2026
- Thayer New City Lake27 km away, 2 reports, last in 2026
- Big Hill Lake29 km away, 26 reports, last in 2026
- Altamont City Lake North32 km away, 4 reports, last in 2021
Questions about Neosho County State Fishing Lake
Is there algae in Neosho County State Fishing Lake right now?
Kansas has no current advisory for Neosho County State Fishing Lake. The most recent sample, on 25 October 2021 at Neosho County Sfl, was at Warning level (microcystin 1.4 µg/L, 409,384 cyanobacteria cells/mL). This site checks KDHE's advisory list every day, but lakes are only sampled after a bloom is reported, so for today's conditions check the KDHE algae bloom map and the signs at the shore.
When was the last algae bloom at Neosho County State Fishing Lake?
The most recent entry in Kansas's data is from 25 October 2021 at Neosho County Sfl: a sample at Warning level (microcystin 1.4 µg/L, 409,384 cyanobacteria cells/mL).
Has Neosho County State Fishing Lake had toxic algae before?
Yes. Blooms are recorded in 2 of the 3 years from 2019 to 2021, most often in August, September and October.
Can dogs swim in Neosho County State Fishing Lake?
Keep dogs out of the water whenever a bloom is reported or the water looks green, scummy or discoloured. Dogs are the animals most often killed by algal toxins because they swallow water and lick their fur. If your dog swims in water that might have algae, rinse it with clean water and call a vet if it vomits, drools, staggers or seems weak.
Can you eat fish caught in Neosho County State Fishing Lake during a bloom?
If you keep fish caught during a bloom, health agencies advise removing the guts and liver and rinsing the fillets in clean water before cooking, because toxins collect most in the organs. Some agencies advise not eating fish from an active bloom at all, so follow local guidance.
About this data
This page uses official records from the Kansas Department of Health and Environment (KDHE), which updated as samples come in, with advisories reviewed through the April to October season. Reports are grouped by waterbody. The site was last rebuilt on 24 October 2026.
States only test some lakes, some of the time, so a lake without a recent report hasn't necessarily been checked. This page is independent, isn't affiliated with the State of Kansas, and isn't health advice. View the source data.